Welcome to our alphabetical list of counties in Colorado A-Z! If you’re planning a big trip to Colorado, or are simply researching the state for fun, keep reading! This comprehensive list answers questions including: How many counties are in Colorado? What were the original 17 Colorado counties? What is the newest county in Colorado? And much more! So keep reading for our alphabetical list of counties in Colorado from A-Z!
A
Adams
Alamosa
Arapahoe
Archuleta
B
Baca
Bent
Boulder
Broomfield
C
Chaffee
Cheyenne
Clear Creek
Conejos
Costilla
Crowley
Custer
D
Delta
Denver
Dolores
Douglas
E
Eagle
Elbert
El Paso
F
Fremont
G
Garfield
Gilpin
Grand
Gunnison
H
Hinsdale
Huerfano
I
J
Jackson
Jefferson
K
Kiowa
Kit Carson
L
La Plata
Lake
Larimer
Las Animas
Lincoln
Logan
M
Mesa
Mineral
Moffat
Montezuma
Montrose
Morgan
N
O
Otero
Ouray
P
Park
Phillips
Pitkin
Prowers
Pueblo
Q
R
Rio Blanco
Rio Grande
Routt
S
Saguache
San Juan
San Miguel
Sedgwick
Summit
T
Teller
U
V
W
Washington
Weld
X
Y
Yuma
Z
Arapahoe, Boulder, Clear Creek, Costilla, Douglas, El Paso, Fremont, Gilpin, Greenwood (later renamed Jefferson), Huerfano, Jefferson, Lake, Larimer, Mountain (later renamed Gilpin), Park, Pueblo, Weld
Arapahoe