Colby is a city located in Kansas. With a 2020 population of 5,305, it is the 59th largest city in Kansas and the 4587th largest city in the United States. Colby is currently declining at a rate of -0.11% annually and its population has decreased by -1.52% since the most recent census, which recorded a population of 5,387 in 2010. Colby reached it's highest population of 5,544 in 1980. Spanning over 4 miles, Colby has a population density of 1,431 people per square mile.
The average household income in Colby is $59,951 with a poverty rate of 12.47%. The median rental costs in recent years comes to $529 per month, and the median house value is $113,500. The median age in Colby is 33 years, 32.1 years for males, and 34.6 years for females. For every 100 females there are 88.7 males.