Route 91 is a short highway in southeastern Missouri. Its northern terminus is at Route 51 in Bollinger County; its southern terminus is at U.S. Route 61 in Morley. The last 22 miles (35 km) southbound run east, not south.

County	Location	mi	km	Destinations	Notes
Scott	Morley	0.000	0.000	Route C (Harding Street) / Stephenson Street	Eastern terminus
		0.663	1.067	US 61 north – Benton	Eastern end of US 61 overlap
		1.194	1.922	US 61 south – Sikeston	Western end of US 61 overlap
	​	6.578	10.586	Route CC north
Stoddard	​	9.891	15.918	Route P south
	​	10.843	17.450	Route P north – Painton
	Bell City	12.259	19.729	Route N south
	​	17.420	28.035	Route 25 south – Bloomfield	Southern end of Route 25 overlap
	​	20.077	32.311	Route OO east
	Advance	22.435	36.106	Route O
		22.637	36.431	Route 25 north – Delta	Northern end of Route 25 overlap
		20.077	32.311	Route C west – Arab
Bollinger	​	28.102	45.226	Route T east – Glennon
	​	28.765	46.293	Route 51 – Zalma, Marble Hill	Northern terminus
1.000 mi = 1.609 km; 1.000 km = 0.621 mi       Concurrency terminus