Green’s Dictionary of Slang

1. roast pork.

1939		Des Moines Register (IA) 7 May Mag. 3/4: Overland trout — roast pork.
2003		(ref. to 1883) The ‘Old’ Oxford Menu at The Oxford Saloon & Cafe Established 1883 🌐 Old Oxford Nickname: [...] ‘Overland Trout’ Roast Pork.

2. bacon.

1887		Shoe and Leather Reporter (US) 43 605/3: His leather overalls are ‘chaps’ [...] Bacon is ‘overland trout,’ and unbranded cattle are ‘mavericks’.
1892		Omaha Dly Bee (NE) 14 Feb. 6/5: A couple of tenderfeet like you don’t know what’s meant by overland trout or Cincinnati chicken.
1905		St. Joseph Dly Press (MI) 23 Dec. 3/3: The cook [...] asked him if ‘he would take overland trout or Cincinnati chicken this morning?’ The cook never omitted these jocular [...] names for bacon.
1917		Seattle Star (WA) 13 July 2/5: Sugar is ‘sand’; beef ‘canned Willie’; milk, ‘canned cow’; bacon is ‘overland trout’ .
1921		Joplin Globe (MO) 21 Dec. 2/6: The menu included [...] ‘overland trout,’ creamed potatoes, candied hams, fresh peas [etc].
1958		McCulloch Woods Words 128: Overland trout—Bacon.
1967		in DARE.