Americans logged roughly 300 million visits to amusement parks last year, and the vast majority surely enjoyed this classic summer diversion. A few hundred clearly did not: More than 2,000 people sustained injuries on amusement park rides, dozens of which required overnight hospital care, according to a state-by-state analysis of data conducted by The Daily Beast.

Federal oversight governing ride accidents is scant; there are no agencies that track accidents in permanent parks. The Consumer Product Safety Commission is tasked with investigating and collecting data on accidents that occur on mobile rides, but its last comprehensive report and analysis was publicly released four years ago.

View Our Rankings of the 15 Rides That Cause the Most Injuries

That leaves a gap in safety regulation, with oversight occurring mostly at the state level. Only about half the states have a regulatory system in place, with varying degrees of detail, covering permanent parks and traveling carnivals.

The Daily Beast obtained data for 2009 from 10 states, in some cases by filing open records requests. Three states—Alaska, Massachusetts and Nebraska—had no reported accidents or fatalities. Reports from California and Pennsylvania accounted for more than two-thirds of the accidents in our database—these states also happen to have large populations and hundreds of theme parks and mobile fairs. In total, we received information on 830 accidents ranging from contusions to concussions to spinal-cord injuries, with roller coasters and water slides accounting for the highest proportion of reported accidents. To achieve a nationwide estimate of accidents-by-ride, we multiplied the accident tallies for each ride by three, to reflect that roughly a third of the nation lives in these 10 states (Alaska, California, Kentucky, Massachusetts, Michigan, Nebraska, Pennsylvania, New Hampshire, New York and North Carolina).

Some rides cause a lot of injuries because they are prevalent and popular (wooden roller coasters). Others are surprising. For the full results, click here.

Clark Merrefield and Lauren Streib conducted these rankings.