Alvan Flanders (* August 2, 1825 in Hopkinton, Merrimack County, New Hampshire, † March 14 1884 in San Francisco, California ) was an American politician ( Republican) and from 1869 to 1870, the eighth governor of Washington Territory.
Flanders attended the common schools and then worked in Boston with the machine trade. In 1851 he moved to Humboldt County in California. There he went into the lumber business. In 1859, he moved to San Francisco, where he was co-founder of the newspaper " San Francisco Daily Times ".
In 1861 he became a deputy in the California State Assembly. In the same year he was employed by the local Federal embossed point (coin). In 1863, Flanders left California and settled in Wallula Washington Territory. He was from 1865 to 1867 head of the post office. Between March 4, 1867 to March 3, 1869, he represented his territory as a non-voting delegate in the House of Representatives of the United States in Washington. At the end of the legislative term, he was appointed by U.S. President Ulysses S. Grant as the successor of Marshall F. Moore as the new governor of the Washington Territory. This office he held until 1870. Thereafter, he moved back to San Francisco, where he pursued his private interests until his death in 1884.