Hermann Adam Widemann (December 24, 1822 – February 7, 1899) was a German-born American businessman, judge and politician.

He came briefly to the California Gold Rush in 1849, but returned after his companion John von Pfister was murdered.

[4] He became sheriff of the island of Kauaʻi in 1854, was elected to the house of representatives in the legislature of the Hawaiian Kingdom in 1855, and in 1863 appointed its circuit judge.

[2]: 180 After leasing Grove Farm to its manager George Norton Wilcox[6] in 1865, he moved to Honolulu to work in the capital.

It was incorporated under the name of "The Hawaiian Bell Telephone Co." and on December 30, 1880, began providing service to the City of Honolulu.

After Mott-Smith was sent to Washington, D.C., to attempt to negotiate a trade treaty, Parker served again briefly until Widemann resumed his duties as minister of finance.

[5] After the 1893 overthrow of the Kingdom of Hawaii, Widemann was sent with Parker and John Adams Cummins to Washington in an attempt to get international support for its restoration.