This Magnolia street, like W Tilden Street, was named by Dr. Francis G. Bryant as part of the 1877 Bay View Addition to the City of Seattle. As I noted in the Tilden Street article, he named his streets for prominent Democratic politicians of the era. Only Tilden and Grover remain. It would appear that the Grover in question was La Fayette Grover, governor of Oregon from 1870 to 1877 and senator from Oregon from 1877 to 1883.
As Wikipedia notes, “During the [disputed] 1876 presidential election, Oregon’s statewide result clearly favored Rutherford Hayes, but then-governor Grover claimed that elector John Watts was constitutionally ineligible to vote since he was an ‘elected or appointed official’. Grover substituted a Democratic elector in his place. The two Republican electors dismissed Grover’s action and each reported three votes for Hayes, while the Democratic elector, C. A. Cronin, reported one vote for Samuel Tilden and two votes for Hayes. The vote was critical because the electoral college without John Watts’s vote was tied 184–184.”
As it turns out, the election was ultimately awarded to Hayes as part of the Compromise of 1877, but it appears Governor Grover did his best to help his fellow Democrat. (There’s more about Oregon’s pivotal role in the Wilamette Week article “That One Time Oregon Decided the Presidential Election.”)
W Grover Street begins at 28th Avenue W at the entrance to Magnolia Manor Park, and runs a tenth of a mile west to 30th Avenue W. It then runs one more block from 31st Avenue W to 32nd Avenue W.