Delco is a common nickname for Delaware County, Pennsylvania. It is a county located in the Commonwealth of Pennsylvania, just outside Philadelphia, with a population of about 576,830 as of the 2020 census

. Delaware County, or Delco, is part of the Philadelphia metropolitan area but is distinct from the city of Philadelphia itself, having its own county laws and government

. Delco is known not only as a place but also as a cultural identity or way of life for its residents

. It has a unique local dialect and community characteristics that differentiate it from Philadelphia proper

. The county includes several municipalities and has a rich history dating back to its creation in 1789 from part of Chester County, named after the Delaware River

. In summary, "Delco" primarily refers to Delaware County, Pennsylvania, a populous suburban county adjacent to Philadelphia, recognized both geographically and culturally as a distinct area