• What to do: Portions and pieces of more than a dozen existing hiking and biking trails are currently open, and several proposed paths are being stitched together by the Erie to Pittsburgh Trail Alliance and Pennsylvania Environmental Council in hopes of developing a contiguous 270-mile mile connection linking Lake Erie to the confluence of the Allegheny, Monongahela and Ohio rivers. The longest stretch is the 43-mile Armstrong Trail in Armstrong and southern Clarion counties, followed by 28 miles of the Allegheny River Trail and the 21-mile Three Rivers Heritage Trail. Some smaller snippets are less than a few miles long. Plans call for the trail system to connect with the Great Allegheny Passage and C&O Canal Trail, which extends to Washington, D.C.

• Contact: www.eriepittsburghtrail.org.

Looking for more from the Post-Gazette? Join PG+, our members-only web site. You'll get exclusive sports content, opinion, financial information, discounts from retailers and restaurants, and more. Our introduction to PG+ gives you all the details.