If all the billboards along Alaska's Seward Highway were laid end to end, they'd reach—nowhere. There are no billboards here, no tollbooths, few towns, and fewer gas stations. But if you're looking for whales and waterfalls, blue glaciers and sharp-toothed mountains, calm trout ponds and stormy ocean fjords, there's enough visual overload here to fill a hard drive with digital pictures.

Starting in Anchorage, the route meanders generally south 127 miles (204 kilometers) from sea to mountains to sea across the Kenai Peninsula, ending in the harbor town of Seward on Resurrection Bay. The U.S. government has named the Seward Highway an All-American Road, suggesting it's a destination unto itself. You could rush through the drive in under three hours, but don't. Devote at least a long weekend to the round-trip to give yourself ample time to explore some of the most appealing and accessible sites in south-central Alaska.

The old joke is that Anchorage, population 283,000, is just 15 minutes from Alaska. Sure enough, when the Seward Highway drops its busy commuter load, it shrinks to two lanes and glides alongside Potter Marsh (mile 117.4). This almost urban wilderness, tucked in a curve between the ocean and the Chugach foothills, is a favorite stop for migratory birds. Eagles soar overhead while waterfowl nest amid vividly green grasses. Two boardwalks (including an 1,100-foot/335-meter addition completed in July 2008) get you closer to the bird-life as well as spawning salmon and wandering moose.

Beyond the marsh, the road squeezes between cliffs and ocean. On one side, gray rock reaches up into Chugach State Park. On the other, silty Turnagain Arm stretches across to the sharp angles of the Kenai Mountains. Stop at the Turnagain House (mile 103.1; tel. 1 907 653 7500) to admire the view and sample fresh Kachemak Bay oysters.

Look down at Bird Creek below the road (mile 101). This fisherman's paradise, with good parking and observation platforms, is almost perfect for kibitzers and photographers as well. "Sightseers love it," says Anchorage sportsman Ralph Portell, showing off a bright silver salmon. "They lean over the railing and ask what you're catching and what you're using." If you're lucky, you might see a Steller sea lion chase a school of salmon into the mouth of the stream.

Just a bit farther, at Bird Point (mile 96), stop to see belugas, their white bodies easily visible in the dark waters.They frequent Turnagain Arm from early summer through September. Ashore, look for the beaver dam in the green boggy area. Across the highway, Dall sheep graze among the rocks on the slopes above. Bird Point also has views of the tidal bore, a two-to-six-foot (one-to-two-meter) surge that occurs when the tide pushes river water upstream.

The turnoff to Girdwood (mile 90), marked by a field of wildflowers in early summer, is a favorite subject of local artists. In tiny Girdwood itself, a mix of funky cabins and pricey ski chalets, flower gardeners make the most of Alaska's long summer daylight. At the Bake Shop (Olympic Mountain Loop, Olympic Circle boardwalk; tel. 1 907 783 2831; www.thebakeshop.com), saucer-size begonias, dahlias, and other blooms on display are nearly as big as the bakery's famous sweet rolls. The expansive gardens of the Hotel Alyeska (1000 Arlberg Ave.; tel. 1 907 754 2111 or 800 880 3880; www.alyeskaresort.com; from $289) fascinate visitors like Jeff Nueman of Fort Worth. "The colors, the variety, the patterns of the flowers—we just don't have this in Texas,".

Slopes of wildflowers greet visitors at Mount Alyeska. Ride a ski tram to a point 2,300 feet (700 meters) up the mountainside (Arlberg Ave.; tel. 1 907 754 2275; www.alyeskaresort.com) for a view that folks up here love to show off to lower-48ers. Hanging glaciers, snowy mountain peaks, and wildlife from tiny marmots to black bears are easy to spot.

A few miles farther down the road, the mountains pull back to reveal green wetlands. Eerie spears of dead, salt-soaked trees are all that's left of a forest destroyed when the 1964 earthquake permeated the soil with seawater. They form a stark foreground to the glaciers of Portage Valley. At mile 78.9, turn off to the Begich, Boggs Visitor Center (Portage Valley Rd.; tel. 1 907 783 2326) on the shores of Portage Lake for views of icebergs.

From there, the road arcs up over 900 feet (274 meters) from near sea level to the broad Turnagain Pass (mile 68.5), a major hot spot for snowmobilers and skiers in winter and for hikers and berry-pickers in summer. Green slopes on either side rise to stony mountaintops flecked with snow even on the hottest days.

Once you're through the pass, the mountains close in around you. Nearly any point along the way is cause to pull over for photos. At mile 54, pull off to look behind you. Mountains fold into one another like reflections in a fun-house mirror, while gold-bearing Canyon Creek foams at their feet. From mile 47 to 18, crystalline lakes pepper the route: Jerome Lake, Tern Lake, massive Kenai Lake, and their companions. The steel-blue waters draw kayakers and canoeists in search of quiet bird watching, fishing, picnicking, and camping. At Summit Lake Lodge (mile 45.5; tel. 1 907 244 2031; www.summitlakelodge.com), the lake view isn't complete without a slab of fresh-baked pie.

At Moose Pass, a sign on a homemade waterwheel with grindstone articulates the local sentiment: "Moose Pass is a peaceful little town. If you have an axe to grind, do it here." The mood of the road is gentler, too, as the mountains back off a bit to give you more breathing room. At mile 14, the Snow River broadens into a set of braided streamlets flowing among tall cottonwood trees. Eagles soar over the gravel beds, and Paradise Peak's ice fields look ready to drop into your lap.

At the end of the road lies Seward. This tidy town of about 3,000 has some 40 B&Bs. Lodgings range from forest cabins to the 1918 Odd Fellows Hall that is now A Swan Nest Inn (504 Adams St.; te. 1 907 224 3080 or 866 224 7461; www.aswannestinn.com; from $120). Several pleasant hotels include the historic Van Gilder downtown (308 Adams St.; tel. 800 204 6835; www.vangilderhotel.com; from $119) and secluded Seward Windsong Lodge (Exit Glacier/Herman Leirer Rd.; tel. 877 777 4079; www.sewardwindsong.com; from $139). Around here, fish is on every menu, from deep-fried halibut by the harbor to fragrant cedar-planked salmon at Ray's Waterfront (1316 Fourth Ave.; tel. 1 907 224 5606). You can catch your own, too, from a charter boat or along the town beach, where seve ral blocks of prime downtown waterfront are available for camping. Fishermen and campers enjoy a view of the busy harbor, where hundreds of white masts and hulls stand out against the dark blue backdrop of the Resurrection Peninsula. Above, Marathon Mountain rears to 3,022 stony feet (921 meters), the steep and challenging site of one of Alaska's most popular foot races.

The crowning view on the Seward Highway is the final one, which, technically, lies at the official start of the road, mile 0. Here, the full glory of Resurrection Bay pens up. Fox Island wades across the mouth of this dramatic fjord. Fishing boats and ayaks ply waters frequented by sea lions, otters, humpback whales, harbor seals, porpoises, and orcas. And simply look up to see a bird-watcher's dream list of birdlife fluttering overhead.

Find a good vantage point at the Alaska SeaLife Center (301 Railway Ave.; tel. 1 907 224 6300 or 800 224 2525; www.alaskasealife.org), a research facility and aquarium devoted to North Pacific marine life. Watching silver salmon leaping in the bay, Mitch Manzo of Anchorage says, "This is the best view on the entire road." He was so taken with Seward that a few years ago he and his betrothed chose a spot just down the beach, near a waterfall, for their wedding. "We wanted everything to be beautiful," says his wife, Debra. "So, naturally, we came here."

Summer is the best time to drive the Seward Highway; see www.wunderground.com/US/AK/Kenai.html for local weather conditions. For more information on the Seward Highway, visit www.byways.org. Also check out The Milepost, a mile-by-mile travel guide to Alaska roads (www.themilepost.com). For details about the resort town of Girdwood, see www.girdwoodalaska.com; for more on Seward, see www.sewardak.org. The local area code is 907 unless otherwise noted. The attractions above begin in Anchorage, the state's largest city.