A new Library of Congress <www.loc.gov> online collection could let you trace your Civil War ancestor's footsteps into battle or see whether soldiers dug trenches on his farm. The nation's top library teamed up with the Library of Virginia <www.lva.lib.va.us> and Virginia Historical Society <www.vahistorical.org> to post images of nearly 3,000 Civil War maps, charts, atlases and sketchbooks at <lcweb2.loc.gov/ammem/collections/civil_war_maps>.

The Library of Congress' own stash of maps, drawn mostly by Union forces or northern commercial firms, depict battles (such as Gettysburg, shown), troop movements and fortifications. The Library of Virginia's 200 maps include Confederate imprints, printed and manuscript maps, and field maps of southwestern Virginia. The Virginia Historical Society posted its Confederate Army Engineer Corps maps, which detail roads, bridges, waterways and major buildings — and identify farms and plantations by the owners' names. You'll also find images from the journals of Robert K. Sneden, an Army of the Potomac mapmaker. His drawings show battle plans and fortification details.