Terrain: vast central plain, mountains in west, hills and low mountains in east; rugged mountains and broad river valleys in Alaska; rugged, volcanic topography in Hawaii
Adventures
in Preservation
AFS
Intercultural Programs
Amizade
Appalachian
Trail Conservancy
Bike & Build
Bob Marshall
Wilderness Foundation
BTCV
Conservation Holidays
BUNAC
Colorado
Trail Foundation.
Concordia
Conservation
VIP
Continental
Divide Trail Alliance
Cultural
Embrace
ecoteer
Ecovolunteer
Foundation
Human Nature
Free
The Children
Global Citizens
Network
Global
Vision International (GVI)
Global Volunteer
Network
Global Volunteers
Habitat
for Humanity
Hudson
River Sloop Clearwater
IndependentVolunteer.org
International
Conservation Volunteer Exchange
International Cultural Youth Exchange
Involvement
Volunteers Association Inc.
International
Volunteers-in-Parks Program
KidsCamps.com
Maple Leaf Adventures
Mercy
Volunteer Corps (MVC)
National
Park Service
Nature
Corps
Oceanic
Society Research Expeditions
OceansWatch
One Brick
Operation Blessing
Pacific
Crest Trail Association
Pacific
Whale Foundation
Passport in Time
Peace
River Refuge and Ranch
Project
Concern International
Project HOPE
Rainbow Center
(horse therapy)
Real
Gap Experience
Service Civil International
SPW-USA
True Travellers
Society
Twin Volunteer
and Work Abroad
Volunteer
Abroad
Volunteer.gov/gov
VolunteerMatch
Volunteer New
Orleans
Volunteers
for International Partnership
Volunteers for Outdoor Colorado
Volunteers for Peace
Voluntours
Whale Watching Spoken
Here
Wilderness
Volunteers
WorldTeach
Youth For Understanding
for many other opportunities go here