Siteseen
Siteseen: American Historama: Westward Expansion
A comprehensive overview of the expansion across the North American continent from the Atlantic to the Pacific in the west from 1841-1850. Provides a summary, list of interesting facts and a timeline.
Smithsonian Institution
National Museum of American History: American Presidency: James K. Polk
Brief biographical sketch of America's eleventh president includes background information on the era in which he served and linked-to objects from the Smithsonian's collections that help define the man and his presidency.