Cattaraugus County is a county in western New York, with one side bordering Pennsylvania. As of the United States 2020 census, the population was 77,042. The county seat is Little Valley. The county was created in 1808 and later organized in 1817.Cattaraugus County comprises the Olean, NY Micropolitan Statistical Area, which is included in the Buffalo-Cheektowaga-Olean, NY Combined Statistical Area. Within its boundaries are the Allegany Indian Reservation of the Seneca Nation of New York, and the Allegany State Park. The Allegheny River runs through the county.

Coudersport is a borough in and the county seat of Potter County, Pennsylvania, United States, located approximately 110 miles (180 km) east by south of Erie on the Allegheny River. The population was 2,546 at the 2010 census.

Warren County is a county located in the U.S. state of Pennsylvania. As of the 2010 census, the population was 41,815. Its county seat is Warren. The county was formed in 1800 from parts of Allegheny and Lycoming counties; attached to Crawford County until 1805 and then to Venango County until Warren was formally organized in 1819.Warren County makes up the Warren, PA Micropolitan Statistical Area.

Allegany County is a county in the Southern Tier of the U.S. state of New York. As of the 2020 census, the population was 46,456. Its county seat is Belmont. Its name derives from a Lenape word, applied by European-American settlers of Western New York State to a trail that followed the Allegheny River; they also named the county after this. The county is bisected by the Genesee River, flowing north to its mouth on Lake Ontario. During the mid-nineteenth century, the Genesee Valley Canal was built to link southern markets to the Great Lakes and Mohawk River. The county was also served by railroads, which soon superseded the canals in their capacity for carrying freight. Part of the Oil Springs Reservation, controlled by the Seneca Nation, is located in the county.