THE CITY is Washington, the year is 1883, and the Washington Monument has a flat top. The Mall, which will become turf for joggers and demonstrators alike, is a swamp. The Capitol sits atop Jenkins Hill, reigning at the center of the city -- the limits of which go only as far north as Florida Avenue.

These landmarks and virtually every block of the city are portrayed on a 19th-century map, a panoply of brownish buildings, patches of green, and a bustling riverfront dotted with ships. The Washington map is one of 58 late 19th- and early 20th-century panoramic views of cities on display at the Library of Congress through May 1. They're also called "bird's eye" views, because they appear to have been drawn from above.

"That's where the artistic talent came in," says Patrick Dempsey, the senior reference librarian in the Library of Congress' geography and maps division, "making it look like it was drawn from an oblique angle."

The cartographers' depictions were so detailed that on some of the maps -- including the one of Washington -- you can find your block. The Washington map may have taken Adolph Sachse two to three years to complete. "First they'd draw a grid of the city," says Dempsey, "then go block by block and draw each building. It was very painstaking work."

Most of the maps were commissioned by chambers of commerce eager to attract people and businesses, Dempsey says. Although most of the blocks were accurately portrayed, the mapmakers often exaggerated the number of ships that a harbor could hold, he says. An illustration of "belching smokestacks was another sign of a city with a healthy industry," says Dempsey. "Sometimes you see open spaces. People get the idea there's room for them to come." The map of Buffalo is like that.

In the margins of the maps are often pictures of houses -- "people would get their residences put in because they paid" -- or of public establishments such as restaurants and hotels. The 1908 Denver map has an inset of the Brown Palace Hotel with the caption "Absolutely Fireproof."

Mapmakers walked the blocks of the city to construct these maps. They hardly got rich, but it was their livelihood. "Many of the artists got their training in the Civil War doing pictures of fortresses and prisoner-of-war camps for the North," says Dempsey.

One of the most prolific mapmakers was Thaddeus Mortimer Fowler, born in Lowell, Mass., in 1842. Fowler was so good at what he did that his 1918 Allentown, Pa., map was thought to have been detailed from an airplane (not so) and aroused the suspicions of Allentown citizens, who thought Fowler was a German spy. He was jailed until his family could drive to Allentown and identify him.

The Library of Congress picked these 58 maps from its collection of 1,700 to illustrate the differences in cities and styles of mapmaking. There is an 1884 map of New York (a Currier and Ives print) with an oversized Brooklyn Bridge, and a pen-and-ink manuscript of Allentown, Pa., with the penciled instructions to the printer visible in the margin. The 1869 map of Baltimore is huge, 64 by 133 inches, and it includes the harbor. There are three of Canadian cities.

There are some puzzling items for the close examiner. On the map of Chester, Pa., two trains on the B & O railroad tracks are headed toward each other. "We don't know if Fowler made a mistake or was playing a joke on someone," says Dempsey.