In 1989 the National Trust for Historic Preservation launched a program that identified 31 lodgings across the country as Historic Hotels of America. It selected hotels that were at least 50 years old and listed in or eligible for the National Register of Historic Places. Today there are more than 170 members, and the rules are flexible enough to include places “recognized locally as having historic significance.” Four of the newest entries reflect that broad scope: a pair of neighboring Hudson River mansions that were once the official residence of Mali’s United Nations envoy; a 1926 hotel in Lawrence, Kansas; a railroad hotel in Roanoke, Virginia, built in 1882; and a 1924 Cincinnati landmark modeled after a seventeenth-century English manor house. The organization offers a wonderfully readable and beautifully illustrated directory for the bargain price of $3.50 (202-588-6295). And if you call 800678-8946 to reserve a room at one of these treasures, a percentage of the rate will go to the nonprofit trust.