Green’s Dictionary of Slang

1. a Floridian.

1865		in B.L. Ridley Battles and Sketches of the Army of Tennessee (1906) 460: The North Carolinians are called ‘Tar Heels;’ [...] Floridians, ‘Gophers’.
1869		‘South-Western Sl.’ in Overland Monthly (CA) Aug. 129: On account of the great number of gophers in that State, and the former use of their skins for money, a Floridian is called a ‘Gopher’.

2. an Arkansan.

1845

Cincinnati Misc. I 240/1: The inhabitants of Arkansas [...] [are called] Gophers [DAE].

3. a Minnesotan.

1866		Amer. Citizen (Butler, PA) 26 Sept. 2/4: Nicknames [...] Minnesota, gopher.
1871		Semi-Wkly Louisianan 31 Aug. 1/3: The Nicknames of the States [...] Maryland,crawthumpers; Michegan, wolverines; Minnesota, gophers; Mississippi, tadpoles; Missouri, pukes.
1880		J.M. Farrar Five Years in Minnesota 166: Gophers are here such a pest to the farmer that Minnesota has been called the ‘Gopher State’.
1962		(con. WWII) J.O. Killens And Then We Heard The Thunder (1964) 411: He was [...] medium-sized and corn-fed and Midwestern Yankee. A Minnesota gopher maybe.

4. (US) an offensive or stupid person.

1865		H.L. Williams Joaquin 85: Give in, you dod-rotted gopher! The woman’s sold you!
1884		in Life 24 Jan. 47: Go yourself, you old gopher [HDAS].
1902		Ade Girl Proposition 11: If any Argument came up on the Veranda or at the Dinner Table he made the others look like Gophers.
1925		Black Mask Aug. III 98: The Gopher had never been a ladies’ man.
1927		(con. 1900s) S. Lewis Elmer Gantry 25: That rusty-haired gopher who had obscenely opposed his election as president.
1939		J. Steinbeck Grapes of Wrath (1951) 62: He’s gettin’ screwy as a gopher.
1942		Berrey & Van den Bark Amer. Thes. Sl. §391.3: rustic, bumpkin, gopher.

5. (US) a primitive form of plough.

1854		Spirit of the Times (N.Y.) 4 Nov. 447/3: I hitched him onto the gopher, and away we went [DA].
1868		Report Committee Agriculture 1867 424: Then there is the ‘scraper,’ the ‘half-shovel,’ ‘gopher,’ and other peculiar forms of implements [DA].
1894		Congressional Record 15 Mar. 2995/1: The gopher is an iron plow [DA].
1953		Randolph & Wilson Down in the Holler 248: gopher: n. A primitive plow.

6. (Can.) a mounted police officer.

1927

T.M. Longstreth Silent Force 154: The Force objected to their name of ‘gophers’.