Round Lake Beach is a city located in Illinois. With a 2020 population of 27,021, it is the 79th largest city in Illinois and the 1418th largest city in the United States. Round Lake Beach is currently declining at a rate of -0.56% annually and its population has decreased by -4.10% since the most recent census, which recorded a population of 28,175 in 2010. Round Lake Beach reached it's highest population of 28,118 in 2010. Spanning over 5 miles, Round Lake Beach has a population density of 5,355 people per square mile.
The average household income in Round Lake Beach is $79,303 with a poverty rate of 10.30%. The median rental costs in recent years comes to $1,281 per month, and the median house value is $135,800. The median age in Round Lake Beach is 32.5 years, 30.5 years for males, and 34.8 years for females. For every 100 females there are 110.7 males.