The Library of Congress discusses your best source of post-Civil War detailed maps:
"While city atlases served a specialized clientele, their rural counterparts, known as county landownership atlases, were a commercial enterprise promoted by subscription campaigns and directed to a wider audience. Based on the pre-Civil War production of wall-sized, single-sheet county landownership maps, atlases showing landownership developed into a popular atlas format starting in the 1860s in the northeastern United States, and expanding into the Midwestern states by the 1870s and 1880s. These commercially published atlases contain cadastral or landownership maps for the individual townships within a county. In addition, they often include county and township histories, personal and family biographies and portraits, and views of important buildings, residences, farms, or prized livestock." ("Atlases." Geography and Maps: An Illustrated Guide. Washington, D.C.: Library of Congress.)
You will have difficulty finding any sort of detailed Civil War period road maps covering the zones of combat, particularly of the South, which is why the armies floundered around when moving to contact. A major reason why Stonewall Jackson was so successful as a commander was that he had directed his engineers to map the Shenandoah Valley. Consequently, he had accurate maps, while his Federal opponents did not. One of Bobby Lee's significant flaws as a commander was that although he controlled the ground in northern Virginia for much of the war he never caused to it be mapped; a fatal flaw for someone who was commissioned as, and supposedly was, an engineer.
The U.S. coast line had been surveyed for years before the Civil War, but the land mass had not. Having learned from their Civil War experiences, and determined never to fight without maps again, the U.S. Army pushed for the creation of the Coast and Geodetic Survey in 1871 to develop detailed topographic maps of the United States.
Regards,
Don Dixon