Frank Dekum (November 5, 1829 – October 19, 1894) was a prominent 19th century fruit merchant, banker, and real-estate investor in Portland, Oregon.

Born in Germany, Dekum emigrated to the north-central U.S. with his family and as a young man went west in search of gold before starting a successful fresh-fruit business in Portland.

Prospering as a merchant, Dekum invested in real-estate, banking, and an early railroad, was a president or board member of many of the city's companies, and was one of 15 men named to Portland's first municipal water committee.

[3] After serving as an apprentice confectioner in St. Louis, Dekum and a friend, Frederick Bickel, went gold prospecting in California and Idaho before settling in Portland.

[2] Amassing wealth from the "largest wholesale fresh-fruit business in the Northwest",[4] Dekum joined "the frenzied real-estate speculations of the early 1860s",[4] and his large holdings included several buildings that bore his name.

[5] Portland historian Joseph Gaston wrote, "It is an interesting and noteworthy fact that he was connected with the construction of every building in whole or in part between First and Third on Washington street...

Decorative machicolations (openings of the sort used in earlier eras for pouring pitch and dropping rocks on attackers) appear in the parapet at the top of the building.

[3] (The two banks occupied the same building and had overlapping directors, including John McCraken, George H. Williams, and Cyrus A. Dolph, as well as Dekum and Thompson.

[14] Most of the railway route ran initially through "virgin timber and scattered clearings",[13] especially north of Albina, where "the country was quite primitive until the broad bottomlands of the Columbia were reached.

[3] In Portland, they lived in a three-story house, built in about 1864, on a tract later defined by Northwest 13th and 14th avenues and Morrison and Yamhill streets, that was at the time well outside the city.

[n 1] The house featured staggered quoins at its corners, a three-bay entrance porch, segmental arched windows, and a conservatory (sun room) on the south.