Carroll Creek is an 8.3-mile-long (13.4 km)[1] tributary of the Monocacy River in Frederick County, Maryland.

The headwaters of the creek are located on the eastern slopes of Catoctin Mountain, southeast of Gambrill State Park.

The stream runs roughly east through the city of Frederick to the Monocacy, which drains to the Potomac River.

The creek was named after Charles Carroll of Carrollton,[2] a Founding Father of the United States who owned large amounts of land in Frederick County.

The innovative design called for the installation of an underground system of concrete conduits able to convey storm-water safely through downtown Frederick.