The creek's watershed extends as far east as
Manchester, Maryland, and includes the towns of
Union Bridge,
Taneytown,
New Windsor and Westminster. The main stem of the creek is formed from the
confluence of
Big Pipe Creek, long, with headwaters near Manchester; and
Little Pipe Creek, long, with headwaters in Westminster. From the confluence, near
Detour, Maryland (), Double Pipe flows west for to its mouth at the Monocacy, which drains to the
Potomac River. The
watershed area of Double Pipe Creek is . Tributaries include Bear Branch, Big Pipe Creek, Little Pipe Creek, Meadow Branch and Sam's Creek. Double Pipe Creek, the portion of Little Pipe Creek west of Union Bridge, and the western section of Sam's Creek form part of the legal boundary between Frederick County and Carroll County. ==Pollution==