Rock Island is a city located in Washington. With a 2020 population of 1,272, it is the 191st largest city in Washington and the 9330th largest city in the United States. Rock Island is currently growing at a rate of 6.18% annually and its population has increased by 61.42% since the most recent census, which recorded a population of 788 in 2010. Rock Island reached it's highest population of 1,272 in 2021. Spanning over 1 miles, Rock Island has a population density of 1,551 people per square mile.
The average household income in Rock Island is $49,875 with a poverty rate of 12.47%. The median rental costs in recent years comes to $618 per month, and the median house value is $156,500. The median age in Rock Island is 31.3 years, 30.7 years for males, and 33.4 years for females. For every 100 females there are 99.0 males.