Utah's 4th congressional district is a congressional district created by the state legislature as a result of reapportionment by Congress after the 2010 census showed population increases in the state relative to other states. Prior to 2010 reapportionment, Utah had three congressional districts.

Salt Lake County is located in the U.S. state of Utah. As of the 2020 United States census, the population was 1,185,238, making it the most populous county in Utah. Its county seat and largest city is Salt Lake City, the state capital. The county was created in 1850. Salt Lake County is the 37th most populated county in the United States and is one of four counties in the Rocky Mountains to make it into the top 100. Salt Lake County has been the only county of the first class in Utah – under the Utah Code is a county with a population of 700,000 or greater. Although, Utah County directly to the south has recently reached this threshold.