What are some places to find topographic maps of Pennsylvania?

The Geology.com and Maps of World websites provide topographic maps of Pennsylvania. Topographic maps are color-coded in order to show the different elevation trends across the state.

The southeastern corner of Pennsylvania has the lowest elevation level, ranging from zero to 150 feet. The lowest point is the Delaware River, which is at sea level. The southeastern quadrant of the state is mostly 150 to 1,200 feet high. The far western portion of the state generally has a range of 600 to 1,800 feet. The highest areas of the state are the northern and central regions, which are typically 1,800 to 3,000 feet high. The highest point is Mt. Davis at 3,213 feet.