(MONEY Magazine) – Unless you live in Minnesota or maybe one of its neighboring states, you've probably never heard of Itasca State Park, which is located in a fairly remote area of Minnesota's northwest quadrant. And that's a shame, because as I discovered while visiting the park two autumns ago, Itasca's gorgeous 32,000-plus acres feature hiking, camping, dozens of lakes and a wildlife sanctuary--and that's just for starters. Moreover, Itasca, whose name is an amalgam of the Latin words for "true head," is the site of the Mississippi River's headwaters, making it a place of historic and geographic significance as well as immense scenic beauty.

My trip left me thinking about the relative anonymity of state parks. Unlike national parks, most of which tend to sound familiar even if you've never visited them (you may not know exactly where Carlsbad Caverns National Park is, but most likely you've at least heard of it, right?), state parks tend to have lower profiles and are often known only to state residents. But as is the case with national monuments, which I wrote about in this column a year ago, just because state parks are overshadowed doesn't mean they're unworthy. Quite the contrary, in fact--many of them are diamonds in the rough; they welcome out-of-staters and they tend to be less crowded than their federal counterparts. And with over 5,000 state parks scattered across America, comprising nearly 12 million acres, there are bound to be plenty of options wherever you're traveling this summer.

My favorite state park, out of the dozens I've visited over the years, is Itasca (Lake Itasca, Minn.; 218-266-2100; www.dnr.state.mn.us/state_parks/itasca/index .html). It was here in 1832 that the explorer Henry Rowe Schoolcraft, led by an Indian guide, found Lake Itasca, the source of the Mississippi. The spot where the river begins flowing off from the lake is popular with visitors, many of whom--myself included--can't resist traversing the river's 30-foot mouth so they can later say, "I walked across the Mississippi!" The Main Park Drive, stretches of which are lined by 275-year-old pine trees, includes stops at two old cemeteries, a lakeshore beach and several excellent nature trails. There's a 16-mile bike loop (bike rentals are available within the park), along with boating and fishing in the summer and snowmobiling and cross-country skiing in the winter.

If you want to stay a while, there's the historic Douglas Lodge (866-857-2757), completed in 1905, plus an assortment of cabins (mine had a prime lakefront location and a lovely fireplace) and more than 200 tent and RV sites for campers. All in all, it's an extremely impressive facility and easily the equal of most National Park Service sites.

A very different kind of natural beauty is on display at John Pennekamp Coral Reef State Park (Key Largo, Fla.; 305-451-1202; www.pennekamppark.com), another site that's a national treasure despite not being a national park. Established in 1960 to protect the continental United States' only living coral reef, Pennekamp spotlights the reef's unique ecosystem, which features dazzlingly colorful coral and nearly 600 species of fish. Scuba and snorkeling tours depart several times a day, and the undersea views are nothing short of spectacular; glass-bottom boat tours are available for those who prefer to observe the reef without getting in the water. Also quite worthwhile (and, as I recently found, an excellent backup activity if ocean conditions on a given day rule out scuba diving and snorkeling) are the park's boat trails: Visitors can rent a canoe or kayak and paddle through several miles of canals surrounded by mangrove trees, whose sinewy branches and root systems form a shadowy, almost spooky canopy. The trail waters are generally shallow and clear, so fish are easy to see--I followed a stingray for several minutes before it scooted out of view. And if you somehow don't see any sea creatures while snorkeling or boating, Pennekamp has its own aquarium, with representative examples of local marine life. Campsites and RV parking are available for overnighters.

At the country's opposite corner is the Oregon coast, which is not only one of America's most beautiful regions but also boasts the highest concentration of state parks in the nation. All of them feature breathtaking views of the Pacific Ocean, but three are of particular interest. At the state's northwest tip is Fort Stevens State Park (near Warrenton, Ore.; 503-861-1671; www .oregonstateparks.org/park_179.php), a former military installation that figures prominently in two little-known chapters of American history. The fort was built for the Civil War--which seems odd, given that the war was several thousand miles away. But the Union was worried that the Confederacy would ally with England and attempt to control the Columbia River. Although that attack never occurred, a Japanese sub fired 17 shells at Fort Stevens during World War II, making it the first (and, until the Sept. 11 attack on the Pentagon, the only) military site in the lower 48 states to come under foreign attack since the War of 1812. All of this is explained at the park's excellent museum. Hiking, biking, camping and a beach are also available.

About 20 miles south of Fort Stevens, Ecola State Park (Canon Beach, Ore.; 503-436-2844; www.oregonstateparks.org/park_188.php) showcases the most photographed view on Oregon's coast. The ocean's magnificent backdrop here includes the huge geological formations Haystack Rock and Neahkahnie Mountain, plus the 1880s-vintage Tillamook Rock Lighthouse. It's the most scenic spot on a very scenic coast--unless that title belongs to Samuel Boardman State Scenic Corridor (north of Brookings, Ore.; 800-551-6949; www.oregonstateparks .org/park _77.php), a 12-mile sliver of a park located in Oregon's southwest corner, studded with 300-year-old spruce trees, small beaches, hiking trails and natural rock arches. It's not to be missed.

As is the case with so many other inconspicuous things, once you start paying attention to state parks, they seem to be everywhere. As I was preparing this article, for example, I happened to read an obituary for Randy Tufts, a spelunker who in 1974 found a previously undiscovered subterranean cave at the bottom of an Arizona sinkhole, somehow managed to keep it a secret for over a decade (even the property owners didn't know of it for the first four years) and then enlisted political support to have it preserved as Kartchner Caverns State Park (Benson, Ariz.; 520-586-4100; www.pr.state.az.us/parkhtml/kartchner.html), which opened to the public in 1999.

I'd never heard of Kartchner before reading Tufts' obit, but you can bet it's on my list now. It's an incredible story--Tufts was so worried that the cave would be exploited and ruined if its existence became public that he convinced his carefully selected allies in the state legislature to use deliberately vague wording when drafting the legislation that created the park. It was so vague, in fact, that many of the other legislators weren't even sure what they were voting on when they appropriated the funds that brought the park into existence.

Happily, Tufts' extraordinary secrecy measures have resulted in what sounds like a fascinating place. Tours of the cave allow visitors to see the magnificent stalactite and stalagmite formations, as well as an extensive fossil record. There are also hiking trails and camping facilities. It's just outside of Tucson, and I'll definitely be stopping by during my next trip to the state.