Black Friday and Cyber Monday are past, so on this Tuesday give a little back...to national parks.

"Giving Tuesday" is the catch phrase for a day to give to your favorite charities, and there are quite a few that support national parks. Here's a short list, though if you look for a friends group that supports your favorite unit of the National Park System, more than likely they're looking for your financial support.

* Friends of Saguaro National Park

In the past two years this friends group has contributed more than $200,000 to Saguaro National Park to support wildlife research, trail work, and environmental stewardship. By 2016 the the friends group hopes to raise well over $1 million to invest in recreational pursuits and environmental education, the preservation and conservation of natural and cultural resources in the park, and environmental stewardship. You can read the strategic plan here and donate to the non-profit organization here. 

* C & O Canal Trust

The folks at the Trust have a modest goal for Giving Tuesday: Just 185 gifts, one for each mile of the Chesapeake and Ohio Canal National Historical Park's towpath. How would the money be spent? Twenty-four dollars allows the Trust to buy enough high-heat paint to keep one campground's worth of grills and fire rings in good condition for two years. Double that to $48, and the organization can buy the paint brushes, rollers, and trays for volunteers to paint every picnic table in the campground. Forty-eight dollars can pay for five pruners to help prune back encroaching vegetation from the Towpath and trails. One-hundred dollars can buy an hour's worth of pothole repairs throughout the park from the towpath crew. Donate to the Trust here.

* Trust for the National Mall

The Trust is partnering with CrowdRise to “build” the world’s first Giving Tower on the grounds of the Washington Monument. Using the Crowdrise Giving Tower app, people can donate to the Giving Tower and, in return, get a brick in the virtual tower with their picture and cause they donated to.  The campaign launched on November 25 and runs through Giving Tuesday. People will be able to visit the Giving Tower in a few real-life locations including on the grounds of the Washington Monument at the National Mall in Washington, D.C., in coordination with The Trust for the National Mall.  All the individual bricks will stack up to create the Giving Tower. As people all over the world donate to the causes they care about, everyone will be able to watch the Giving Tower grow.

* Golden Gate National Parks Conservancy

The Conservancy has enticed FedEx to join their Giving Tuesday challenge by making a $10,000 contribution that will double the impact of your donation. Donate today to make the most of your gift and the FedEx challenge grant. Today only, your donation to the Golden Gate National Parks Conservancy will go twice as far for hiking and biking trails, habitat restoration projects, the protection of endangered species, and youth education.

* The National Park Trust

This national organization helps parks across the country in many ways, whether it's funding research projects, helping with preservation needs, or connecting kids with parks or educating them through the Buddy Bison youth education program, the Trust is a vital non-profit organization for nationa parks. Visit the Trust's homepage to donate.

* Friends of Acadia

Jordan Pond, Cadillac Summit, Bass Harbor Head Light, Schoodic Point, Sand Beach, Thunder Hole...which is your favorite spot in Acadia National Park? Celebrate GivingTuesday by letting Friends of Acadia know. Go to this page and then click on the photo of your favorite “Iconic Acadia” spot to make a donation and cast your vote, The friends group will announce the winning location on Wednesday. Any amount you give to Friends of Acadia will help us protect your favorite place—and all of Acadia National Park.