The Pioneer Base Ball Club, known also as the Oregon Pioneers and the Portland Pioneers, was an American amateur baseball team that represented East Portland and Portland, Oregon in the mid-to-late 1860s. It was the first baseball team organized in the state of Oregon. The first mention of the team came on August 3, 1866, when the Pioneer Club played an intra-squad game at their home field in East Portland. The Pioneers attempted to construct a full season in 1867. They played against other amateur teams from Vancouver, Washington, Portland and Oregon City, Oregon. In September 1867, the Pioneers issued a challenge to any amateur team in Oregon and Washington Territory to square-off at the Oregon State Fair. Two teams, the Willamettes of Portland and Clackamas of Oregon City, accepted the challenge.

Frank Manley Warren Sr. was a prominent American businessman from Oregon who made his fortune in the salmon canning industry. The community of Warrendale, Oregon, the site of one of his canneries, was named for him. He died in the sinking of Titanic.