America's state parks are having a moment — and it's easy to see why. Many cost nothing to enter, they rarely feel crowded, and some of the scenery rivals anything you'd queue hours for at a national park. A new roundup highlights 12 worth building a trip around, spanning Ohio to Iowa.

In Ohio, Hocking Hills State Park packs cliffs, waterfalls and rock formations into 2,356 acres laced with around 25 miles of trails. Old Man's Cave, the 700-foot-wide Ash Cave and Cedar Falls are the headliners, and some routes, like the Ash Cave Gorge Trail, are wheelchair accessible. Tent sites run from about $25 a night, cabins from around $100.

Pennsylvania fields two entries. Ricketts Glen State Park crams 22 waterfalls into 13,000 acres — the 7.2-mile Falls Trail passes 21 of them, including the 94-foot Ganoga Falls. Camping starts at $15. Further west, Ohiopyle State Park is the pick for paddlers, with white-water rafting and kayaking on the Youghiogheny River plus the 30-foot Cucumber Falls a short family-friendly walk away.

Tennessee's Fall Creek Falls State Park, about 62 miles north of Chattanooga, guards one of the tallest free-falling waterfalls in the eastern US — a 256-foot plunge visible from both the gorge rim and its base. In West Virginia, Blackwater Falls' tannin-stained, amber-dark cascade drops 60 feet into a gorge, and in winter the park adds a conveyor-lift sled run.

For something different, Mount Magazine State Park in Arkansas sits across the entire summit of the state's highest point — you drive up, then wander a cliff-rimmed plateau where 94 butterfly species flit and hang gliders launch from the ridges. Arkansas's Petit Jean State Park counters with the 95-foot Cedar Falls and Native American rock art near Rock House Cave.

Missouri also lands twice. Johnson's Shut-Ins is a natural water park: chutes and plunge pools scoured through volcanic rock in the Black River, with collared lizards sunbathing on the rocks. And Ha Ha Tonka, near Camdenton, is the wildcard — a ruined early-1900s stone castle on a bluff above the Lake of the Ozarks, plus a 300-foot sinkhole and a spring pumping out 58 million gallons a day. Note it's day-use only, no camping.

Rounding out the list: Kentucky's Natural Bridge, a 78-foot sandstone arch reachable on foot or via a retro chairlift; Illinois's Starved Rock, with 18 glacially carved sandstone canyons about 90 miles from Chicago; and Iowa's Pikes Peak State Park, where a 500-foot bluff delivers a Mississippi River panorama that peaks in autumn.

All 12 are free to enter — you'll only pay for camping or cabins, generally from $15 to $35 a night. For travellers priced out of or tired of the big national parks, these offer the same drama with a fraction of the traffic, and most work equally well as a weekend road-trip stop or a longer hiking base.