County Map Series (1:50,000)
Colorado and Pennsylvania the only other states where USGS publishes county maps.
Middlesex County Connecticut Topographic Map
The County Map Series is almost as detailed as the primary series. They are an excellent value because a dozen primary series maps could be needed to cover one county. Some county maps are 40x52 inches.
Area covered and sheet size varies depending with the size of the county. Larger counties require more than one map. Each county is shown in silhouette, meaning that no detail outside the county boundary is shown. County maps come folded to booklet size.
Scale 1:50,000; 1 inch = about 8/10 mile.
This three inch section of the Middlesex County map displays part of the Connecticut River Valley. The 20 foot contour interval clearly describes low islands and steep bluffs. As on the primary series maps, roads, buildings and water features are shown in great detail.