WASHINGTON, D.C. ? Civil War buffs are getting access to a treasure trove of information: thousands of original maps and diagrams of battles and campaigns between 1861 and 1865, all posted on the Internet.

The Library of Congress is posting 2,240 maps and charts, and 76 atlases and sketchbooks, while The Virginia Historical Society and the Library of Virginia are adding about 600 items. Much of the collection is online now; the rest will be by the spring.

The items depict troop positions and movements, as well as fortifications. There also are reconnaissance maps, sketches, coastal charts and theater-of-war maps.

One plan of the Mississippi port of Vicksburg was done in 1863, the year Union Gen. Ulysses S. Grant forced its surrender on July 4 in one of the war’s most decisive operations. It gave the Union control of the river and cut the Confederacy in two. It also won the attention of President Lincoln to his most successful commander.

Items already posted can be seen at http://memory.loc.gov/ammem/collections/civil_war_maps.