National Register of Historic Places listings in Mississippi
This is a list of properties and districts in Mississippi that are listed on the National Register of Historic Places. There are 1,407 sites distributed among all of Mississippi's 82 counties; the locations of National Register properties and districts, may be seen in an online map by clicking on "Map of all coordinates". This National Park Service list is complete through NPS recent listings posted April 12, 2019; the following are approximate tallies of current listings by county. These counts are based on entries in the National Register Information Database as of March 13, 2009 and new weekly listings posted since on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings and the counts here are approximate and not official. New entries are added to the official Register on a weekly basis; the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number.
List of National Historic Landmarks in Mississippi List of Mississippi Landmarks
National Register of Historic Places listings in Iowa
This is a list of properties and historic districts in Iowa that are listed on the National Register of Historic Places. There are listings in all of Iowa's 99 counties; this National Park Service list is complete through NPS recent listings posted April 12, 2019. The following are approximate tallies of current listings by county; these counts are based on entries in the National Register Information Database as of April 24, 2008 and new weekly listings posted since on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings and the counts here are approximate and not official. New entries are added to the official Register on a weekly basis; the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number. The numbers of NRHP listings in each county are documented by tables in each of the individual county list-articles.
List of National Historic Landmarks in Iowa
Truss bridge
A truss bridge is a bridge whose load-bearing superstructure is composed of a truss, a structure of connected elements forming triangular units. The connected elements may be stressed from tension, compression, or sometimes both in response to dynamic loads. Truss bridges are one of the oldest types of modern bridges; the basic types of truss bridges shown in this article have simple designs which could be analyzed by 19th and early 20th-century engineers. A truss bridge is economical to construct; the nature of a truss allows the analysis of its structure using a few assumptions and the application of Newton's laws of motion according to the branch of physics known as statics. For purposes of analysis, trusses are assumed to be pin jointed; this assumption means that members of the truss will act only in compression. A more complex analysis is required where rigid joints impose significant bending loads upon the elements, as in a Vierendeel truss. In the bridge illustrated in the infobox at the top, vertical members are in tension, lower horizontal members in tension and bending, outer diagonal and top members are in compression, while the inner diagonals are in tension.
The central vertical member stabilizes the upper compression member. If the top member is sufficiently stiff this vertical element may be eliminated. If the lower chord is sufficiently resistant to bending and shear, the outer vertical elements may be eliminated, but with additional strength added to other members in compensation; the ability to distribute the forces in various ways has led to a large variety of truss bridge types. Some types may be more advantageous when wood is employed for compression elements while other types may be easier to erect in particular site conditions, or when the balance between labor and material costs have certain favorable proportions; the inclusion of the elements shown is an engineering decision based upon economics, being a balance between the costs of raw materials, off-site fabrication, component transportation, on-site erection, the availability of machinery and the cost of labor. In other cases the appearance of the structure may take on greater importance and so influence the design decisions beyond mere matters of economics.
Modern materials such as prestressed concrete and fabrication methods, such as automated welding, the changing price of steel relative to that of labor have influenced the design of modern bridges. A pure truss can be represented as a pin-jointed structure, one where the only forces on the truss members are tension or compression, not bending; this is used by the building of model bridges from spaghetti. Spaghetti is brittle and although it can carry a modest tension force, it breaks if bent. A model spaghetti bridge thus demonstrates the use of a truss structure to produce a usefully strong complete structure from individually weak elements; because wood was in abundance, early truss bridges would use fitted timbers for members taking compression and iron rods for tension members constructed as a covered bridge to protect the structure. In 1820 a simple form of truss, Town's lattice truss, was patented, had the advantage of requiring neither high labor skills nor much metal. Few iron truss bridges were built in the United States before 1850.
Truss bridges became a common type of bridge built from the 1870s through the 1930s. Examples of these bridges still remain across the US, but their numbers are dropping as they are demolished and replaced with new structures; as metal started to replace timber, wrought iron bridges in the US started being built on a large scale in the 1870s. Bowstring truss bridges were a common truss design during this time, with their arched top chords. Companies like the Massillon Bridge Company of Massillon and the King Bridge Company of Cleveland, Ohio became well-known, as they marketed their designs to cities and townships; the bowstring truss design fell out of favor due to a lack of durability, gave way to the Pratt truss design, stronger. Again, the bridge companies marketed their designs, with the Wrought Iron Bridge Company in the lead; as the 1880s and 1890s progressed, steel began to replace wrought iron as the preferred material. Other truss designs were used during this time, including the camel-back.
By the 1910s, many states developed standard plan truss bridges, including steel Warren pony truss bridges. As the 1920s and 1930s progressed, some states, such as Pennsylvania, continued to build steel truss bridges, including massive steel through-truss bridges for long spans. Other states, such as Michigan, used standard plan concrete girder and beam bridges, only a limited number of truss bridges were built; the truss may carry its roadbed in the middle, or at the bottom of the truss. Bridges with the roadbed at the top or the bottom are the most common as this allows both the top and bottom to be stiffened, forming a box truss; when the roadbed is atop the truss it is called a deck truss. When the truss members are both above and below the roadbed it is called a through truss, where the sides extend above the roadbed but are not connected, a pony truss or half-through truss. Sometimes both the upper and lower chords support roadbeds; this can be used to separate rail from road traffic or to separate the two directions of automobile traffic and so avoiding the likelihood of head-on c
Farmington River
The Farmington River is a river, 46.7 miles in length along its main stem, located in northwest Connecticut with major tributaries extending into southwest Massachusetts. Via its longest branch, the Farmington's length increases to 80.4 miles, making it the Connecticut River's longest tributary by a mere 2.3 miles over the major river directly to its north, the Westfield River. The Farmington River's watershed covers 609 square miles; the river played an important role in small-scale manufacturing in towns along its course, but it is now used for recreation and drinking water. The Farmington River Watershed Association is a non-profit organization for conservation and preservation of this river. Headwaters for both main branches of the Farmington River, referred to as the East Branch and West Branch, are found in southwestern Massachusetts, though only the West Branch begins north of the Connecticut border; the West Branch rises at the outlet of Hayden Pond in Massachusetts. In 1994, a 14-mile stretch of the branch was designated a National Scenic River.
The East Branch begins in Hartland, Connecticut at the confluence of Pond and Valley Brooks. However, this branch has been impounded along the first 11 miles of its course to form the Barkhamsted Reservoir and Lake McDonough; the East Branch and West Branch join in New Hartford, Connecticut just about one mile south of Lake McDonough. Upper reaches of the river flow southward, but the river turns northward in Farmington and runs north and east until it flows into the Connecticut River in Windsor, Connecticut. There are several whitewater sections. One of these, the so-called "Upper Farmington" section of the West Branch in New Boston, Massachusetts, is about 7 miles long, it is Class 2 through farm and woods scenery to an iron bridge, where kayak and canoe slalom races are held. Below the bridge the river becomes Class 3-4 technical at low water, technical and pushy at higher water, with a short gorge with several abrupt drops; the biggest of these is about four feet at Decoration Rock. Below, the river continues technical with many rocks and constant maneuvering required.
The river is leading through larger drops at Battering Ram rapid and Corkscrew. It flattens to Class 2 until a final, ledge rapid at Bear's Den, just above the reservoir; the Upper Farmington is runnable during fall dam releases, is a much better run at levels of about 600 cubic feet per second, or about 5 feet on the internet gauge for that section. A second whitewater section is found in Tariffville, one mile of technical Class 3 water, runnable all year round; the river is paddled at levels between 1.5 and 2.75 feet on the internet gauge. This section includes the famous T-ville Hole, where kayakers can practice hole surfing and freestyle moves above a flat pool. Below the Hole is a broken dam, where the river funnels through an abrupt four foot drop into a large wave; this area is popular with swimmers in summer, it is risky due to heavy currents and undercut rocks. There have been at least three fatal drownings in the Tariffville Gorge section people who were not properly prepared or trained for the heavy rapids and pinning obstacles in the gorge.
Paddlers without helmets and Class 3 whitewater skills should end downriver trips at Tariffville Park, just above the start of the gorge. Other whitewater areas include Satan's Kingdom in New Hartford, popular with tubers, the Crystal Rapids section in Collinsville and Unionville, about four miles of Class 1-3 training waters with a bicycle and pedestrian path on the right side of the river. Entrance to the park is free. A service will pick tubers up and drop them off at certain points; the west branch of the river includes two hydroelectric dams in West Hartland and Colebrook, run by Connecticut's Metropolitan District Commission. The largest dam on the east branch is the Saville Dam; the Rainbow Dam, a 68-foot dam with a hydroelectric generator and a fish ladder, dams the river at Windsor, a few miles before the river flows into the Connecticut River. A number of other dams have been built on the river since European settlement to power mills and other industry. A few, such as in Collinsville, are still intact.
The Collinsville Renewable Energy Promotion Act would instruct the Federal Energy Regulatory Commission to issue licenses to the town of Canton, Connecticut to restart two small power dams along the river. The bill passed the United States House of Representatives on February 12, 2013, but has not yet become law. Water released from or flowing over the Otis Reservoir dam enters the Farmington River just North of Reservoir Road in Otis, Massachusetts. Significant quantities of water are released during the fall in order to drop the reservoir water level for the winter; the Farmington River was the home of a Native American indigenous people called the Massaco, who inhabited the Simsbury and Canton area of Connecticut. One of the eighteen bands of the Wappinger, they lived and fished along the river, which acquired the name "Farmington" The land of the Massaco was subsequently purchased by the Dutch; this and its settlement during the era of the Connecticu
National Register of Historic Places listings in Alaska
This is a list of properties and districts listed on the National Register of Historic Places in Alaska. There are 400 listed sites in Alaska; each of the state's 28 boroughs and census areas has at least two listings on the National Register, except for the Kusilvak Census Area, which has none. This National Park Service list is complete through NPS recent listings posted April 12, 2019; the following are approximate tallies of current listings in Alaska on the National Register of Historic Places. These counts are based on entries in the National Register Information Database as of April 24, 2008 and new weekly listings posted since on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings, the counts here are not official; the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number. List of National Historic Landmarks in Alaska Aviation history in Alaska — National Register of Historic Places travel itinerary
National Register of Historic Places listings in Hawaii
This is a list of properties and historic districts in Hawaii listed on the National Register of Historic Places. More than 340 listings appear on all but one of Hawaii's main islands and the Northwestern Islands, in all of its five counties. Included are houses, archeological sites, ships and various other types of listings; these properties and districts are listed beginning at the northwestern end of the chain. This National Park Service list is complete through NPS recent listings posted April 12, 2019; the following are approximate tallies of current listings by county. These counts are based on entries in the National Register Information Database as of April 24, 2008 and new weekly listings posted since on the National Register of Historic Places web site, all of which list properties by county. There are frequent additions to the listings and occasional delistings, the counts here are approximate and not official. New entries are added to the official Register on a weekly basis; the counts in this table exclude boundary increase and decrease listings which modify the area covered by an existing property or district and which carry a separate National Register reference number.
The number of NRHP listings on each island are documented by tables in each of the individual island lists, the number of listings in each county is determined by adding the totals of the islands in that county. Kalawao and Maui counties are the sole exception: Kalawao County is a peninsula on Molokai, otherwise a part of Maui County. Many small islands, all uninhabited, lie northwest of Kauai, they are included despite the vast distance between them and Oahu. Kauai is the northernmost of the major islands of Hawaii, except for Niihau, the westernmost. Together with Niihau, it forms Kauai County. Oahu is the only major island in Honolulu County; the location of the city of Honolulu, Oahu is the most populous island in the state. Molokai is the northernmost of the islands of Maui County. Unlike every other island in the state, it is divided between two counties: Kalawao County consists of the island's northern peninsula. Lanai is the smallest of the populated islands of Maui County, lying between the islands of Maui and Molokai.
Maui is the easternmost island of Maui County. Kahoolawe is the southernmost island of Maui County. Alone among the state's major islands, it is uninhabited; the government of the island of Hawaii is Hawaii County, the only county that covers one island, the largest in area in the state. There are 67 properties and districts on the island, including 10 historic districts, six National Historic Landmarks, one, a National Historic Landmark District. Historic Hawaii Foundation Inventory of Historic Properties on official Hawaii State web site
National Register of Historic Places listings in Louisiana
This is a list of properties and districts in Louisiana that are listed on the National Register of Historic Places. There are listings in each of Louisiana's 64 parishes; the locations of National Register properties and districts, may be seen in a map by clicking on "Map of all coordinates". The following are approximate tallies of current listings by parish; these counts are based on entries in the National Register Information Database as of April 24, 2008 and new weekly listings posted since on the National Register of Historic Places web site. There are frequent additions to the listings and occasional delistings and the counts here are approximate and not official. New entries are added to the official Register on a weekly basis; the counts in this table exclude boundary increase and decrease listings which only modify the area covered by an existing property or district, although carrying a separate National Register reference number. This National Park Service list is complete through NPS recent listings posted April 12, 2019.
List of National Historic Landmarks in Louisiana List of bridges on the National Register of Historic Places in Louisiana
