California's homeless population increased so much in 2019 that it caused a nationwide rise in overall homeless, despite declines in more than half of the states this year, according to new federal data.

Every year, the U.S. Department of Housing and Urban Development uses data reported by about 3,000 cities and counties to estimate the nation's homelessness population. The data is used in tandem with snapshot estimates by "Continuums of Care" planning agencies of individuals and families "living in emergency shelters, traditional housing programs and unsheltered settings" on a single night in January to assess "the scope of homelessness and (measure) progress toward reducing it," according to a department press release.

Overall, 567,715 persons experienced homelessness on a single night in 2019 – an increase of nearly 15,000 people, or 2.7%, since 2018, according to the department's press release, released Friday. The increase marks the third year in a row that the overall homeless population in the U.S. has gone up, but homeless populations varied by geographic location.

Twenty-nine states and the District of Columbia witnessed declines in homelessness year over year, according to data on point-in-time estimates by state. Connecticut (-23.7%), Maine (-16.3%), Iowa (-15.8%), Vermont (-15.6%) and Delaware (-14.9%) were the states that experienced the largest percentage decreases in their total homeless populations between 2018 and 2019. Meanwhile, 21 states reported increases in the number of people experiencing homelessness in 2019, with New Mexico (27%), California (16.4%) and Idaho (15.1%) experiencing the largest percentage increases.

The most populous state in the United States, California saw the largest spike to its homeless population with an increase of 21,306 people in 2019, which was more than the total national increase of every other state combined. The Golden State's overall homeless population was estimated to be 151,278 people in 2019.

"As we look across our nation, we see great progress, but we're also seeing a continued increase in street homelessness along our West Coast where the cost of housing is extremely high," said Housing and Urban Development Secretary Ben Carson in a statement.

"In fact, homelessness in California is at a crisis level and needs to be addressed by local and state leaders with crisis-like urgency," he said. "Addressing these challenges will require a broader, community-wide response that engages every level of government to compassionately house our fellow citizens who call the streets their home."

Notably, homelessness among veterans and families with children continued to fall in 2019, declining 2.1% and 4.8%, respectively, from the prior year.