Parker is a city located in Armstrong County, Pennsylvania, United States. It is in the extreme northwestern portion of the county. The population was 840 at the 2010 census. The city was named for Judge John Parker, a lead surveyor of Lawrenceburg and founder/owner of Parker's Landing, the two villages combined to create Parker.
Parker is sometimes referred to as the "Smallest City in the USA." Parker was incorporated as a city on March 1, 1873, by special state legislation in the midst of the northwestern Pennsylvania oil boom. The new municipality was called "Parker" and made up the earlier villages of Parker's Landing (on the Allegheny River) and Lawrenceburg (on the bluff above the river). Residents assumed that Parker would quickly become a major population center, and at the height of the oil boom, the population of Parker grew to over 20,000. The boom quickly went bust, however, and by the 1880s the "city" returned to its historic small village size -- a population of approximately 1,000.
Parker received national attention again in 2014 when a massive ice jam along the Allegheny River formed and started some minor flooding. The jam was so massive that it attracted tourists to the area, and a local bar even named a drink after the ice jam. The ice jam was severe enough that the National Weather Service issued a flood warning for the area in case the ice started melting.