Wednesday marks the 25th anniversary of the 1980 eruption of Mount St. Helens, and there are special events in the nearby town of Castle Rock starting this weekend, plus free admission Wednesday to the Mount St. Helens National Volcanic Monument. The monument also hosts a number of special programs in the coming week.

To help you plan a visit, the Internet offers a number of useful Web sites:

Your main Internet destination is, of course, the Mount St. Helens National Volcanic Monument Web site — www.fs.fed.us./gpnf/mshnvm — a source of information on just about everything you'll want to know. (For specifics on the anniversary and related events, go directly to www.fs.fed.us/gpnf/msh25/index.shtml.) From the home page, there are links to everything from the weather to hiking trail conditions, from panoramas and waterfalls to campgrounds. Click on "Attractions" for details on what there is to see on all sides of the mountain. And be sure to check out the photo gallery and "Live VolcanoCam," for days when the volcano isn't obscured by clouds.

Among recent news posted on the Web site: The Johnston Ridge Observatory, on a stretch of Highway 504 closed since Oct. 2 because of volcanic activity, reopened last Friday.

The Johnston Ridge facility and the Coldwater Ridge Visitor Center now are operating on summer hours, 10 a.m. to 6 p.m. daily.

If you want to sample technical information about the volcano, the Cascades Volcano Observatory has a set of links — vulcan.wr.usgs.gov/Volcanoes/MSH/framework.html — where you can check status reports, read about the 1980 eruption in-depth and get a sample of seismograph readings.

Admiring Mount St. Helens isn't the only thing to do in the area. The national monument sits within sprawling Gifford Pinchot National Forest — www.fs.fed.us/gpnf — where you can camp, hike and try your luck with the local fish. Some hiking or mountain climbing might be restricted because of the volcano's activity.

Mount St. Helens also sits in Cowlitz County, which has a tourism Web site — www.co.cowlitz.wa.us/tourism/Commty/Commty.htm — where you'll find directories of places to stay and links to related sites, including one for the scenic North Fork of the Lewis River — www.lewisriver.com — and a Mount St. Helens photo gallery. The county's biggest city is Longview — 205.238.37.7/index.html — which boasts "100 plus things to do."

On the north side of the volcano, Lewis County — www.tourlewiscounty.com — offers hiking, camping, fishing and hundreds of miles of scenic mountains, streams and forest. Its cities of Centralia, Chehalis and others offer additional places to stay. Click on "Places to Go" for directions to historic spots; suggestions for walking tours; and "Excursions," a diverse group of activities that includes scenic drives, fall foliage and shopping for antiques.