Organizations
ACRES Land Trust is Indiana's oldest land trust, founded in 1960. It protects thousands of acres and provides access to dozens of preserves, mostly in northeastern Indiana.
This Indianapolis-based chapter of the National Audubon Society was founded in 1938. It maintains an active schedule of events, including monthly meetings at the Holliday Park Nature Center in Indianapolis and numerous field trips.
CILTI is an Indianapolis-based land trust that protects thousands of acres through direct acquisition, conservation easements, or management agreements. Several of its preserves are open to the public.
Central Indiana Wilderness Club
CIWC was founded in 1982 with the goal of providing affordable, guided adventure trips. It maintains an incredible trip calendar ranging from short local jaunts to epic journeys to places all over the United States.
Formerly Indiana Recycling Coalition. Educates, advocates, and innovates as part of an effort to reduce waste and help create a more circular economy.
CAC describes themselves as Indiana's oldest and largest consumer and environmental advocacy organization. Their focus seems to be on energy and utilities, but of course everything is connected and those things have major environmental impacts.
Clear Lake Township Land Conservancy
A land trust that operates in Clear Lake Township in Steuben County. As of 2025 they protect 19 preserves comprising more than 145 acres.
Promotes sustainability through education and demonstration. Owns and manages a really nice 130 acre property with more than three miles of trails near Centerville, in Wayne County.
Works to promote, preserve, protect, and enhance Eagle Creek Park. Eagle Creek Park is on the northwest side of Indianapolis and is one of the largest city parks in the United States. The park includes an Earth Discovery Center, ornithology center, marina, swimming area, miles of trails, and a host of other activities.
Earth Charter Indiana exists to inspire and advance sustainable, just and peaceful living in Indiana by promoting the values and principles of the Earth Charter, to wit: (1) Respect and care for the community of life, (2) Ecological integrity, (3) Social and economic justice, and (4) Democracy, non-violence and peace.
Hosts an annual Earth Day Festival every April.
A chapter of the National Audubon Society. They offer field trips and have monthly meetings with programs.
Dedicated to providing support for the park, which is in north-central Indianapolis.
Supporting the goals of wildlife conservation and habitat restoration at Goose Pond Fish and Wildlife Area, an amazing marshland and prairie restoration project that encompasses more than 9,000 acres in Greene County.
Holliday Park is in north-central Indianapolis. It features an extensive trail network and a nature center with meeting rooms that host the meetings of numerous environmentally-related organizations, including some on this list.
The Friends work with the lake community, government, and local businesses to protect and enhance Lake Monroe (or Monroe Lake, according to the Indiana Department of Natural Resources) and its watershed.
Sugar Creek flows through west-central Indiana, and drains about a half million acres, mostly in Boone County and Montgomery County, as well as parts of five others. Founded in 1987, Friends of Sugar Creek has worked to protect, restore, and promote appreciation of Sugar Creek and its watershed ever since.
Protecting, restoring and fostering stewardship of the St. Joseph River Watershed, which drains over a million acres in northern Indiana, including all of Lagrange County, nearly all of Elkhart County, most of Noble County and Steuben County, and parts of three others.
FOWR's goal is "...to sustain the long-term viability of the White River for future generations. Programs include river cleanups, outdoor recreation, and watershed restoration.
Projects include advocating for trail planning and investment in trail infrastructure and helping purchase land for trail development.
While based in Paoli (Orange County), Heartwood is a regional network that spans 18 states. Their focus is on forests and protecting forests through education, advocacy, and empowering citizens.
HEC is a large, well-staffed, and well-connected organization involved in many different initiatives. Their website calls out a handful of crucial issues: (1) transitioning to a sustainable energy economy; (2) modernizing transportation; (3) preserving open spaces; (4) making farming more sustainable and healthier; (5) protecting our public health.
This group does more than advocate for hiking trails - they build and maintain trails, most notably much of the 42-mile Tecumseh Trail, one of the longest in the state. Among other things, they have trail workdays every third Saturday.
Founded in 1898, IAS states that they are "the oldest conservation organization continuously operating in Indiana". In fact, they predate, and are independed of, the National Audubon Society. Their focus is on birds, and they conduct field trips across the state and they own and maintain a the 700 acre Mary Gray Bird Sanctuary in Fayette County.
The Alliance works to protect and preserve forests, including urban forests, and advances forest science, particularly through surveying biological diversity.
IKC helps to protect caves and their ecosystems. Activities include participation in a biennial bat census, active monitoring of other species, ownership and management of caves, and sponsorship of Under-Earth Day.
Indiana Lakes Management Society
ILMS promotes and encourages the understanding and comprehensive management of lakes and watersheds and their watershed ecosystems.
Indiana Land Protection Alliance
ILPA is network of land trusts, conservation partners, and community members that champions land and water protection for all of Indiana.
Founded in 1993, INPS now has more than a thousand members and seven chapters across the state. The organization promotes the appreciation, preservation, conservation, utilization and scientific study of the flora native to Indiana.
Rather than raising funds for property acquistion and maintenance, IPA focuses on advocacy, research, education, and providing grants for local friends groups or for specific projects.
Phenology is the study of periodic events and timing of life cycles, like when flowers bloom and migratory birds arrive at their nesting grounds. This information is critically important when trying to understand the impacts of climate change. Indiana Phenology is a volunteer-run nonprofit that partners with communities, schools, and individuals to gather scientific data that helps build a more resilient world and protects Indiana's natural treasures.
Izaak Walton League of Indiana
The League is over a hundred years old and has scored many remarkable successes in defense of water quality, habitat, and species protection. While membership is perhaps not what it once was, there are still many active chapters in Indiana; some own property for meetings and activities.
KIBI plants trees, creates and maintains greenspaces, cleans up litter, and otherwise works to make Indianapolis cleaner, greener, and safer for everyone.
The Little River drains much of southwest Allen County before joining the Wabash River just west of Huntington. The LRWP works to restore and protect wetlands in the watershed of the Little River. It protects more 1,300 acres in multiple preserves, many with hiking trails.
Mud Creek arises in southwest Madison County, then meanders south-southwest to its eventual confluence with Fall Creek in Fort Harrison State Park. The Conservancy owns several nature preserves that provide an alternative to development pressures affecting the watershed.
The Nature Conservancy is a global organization with a substantial footprint right here in Indiana. They steward dozens of ecologically-significant properties around our state, and frequently help other organizations do the same.
NICHES serves thirteen Indiana counties from its base in Lafayette. It owns numerous nature preserves, including many that are open to the public, and quite a few with trails.
Oak Heritage Conservancy is a land trust that works in southeast Indiana. They own at least a dozen preserves.
Ouabache Land Conservancy is a land trust that focuses on six west-central Indiana counties centered around Terre Haute. As of 2025 they own five nature preserves and hold conservation easements on five other properties, altogher totalling more than a thousand acres.
Oxbox works at the confluence of the Great Miami and Ohio Rivers, where it protects more than 1,600 acres of floodplain. This provides breeding sites, shelter, food, and resting places for the thousands of species that thrive in the floodplain, as well as preventing development.
In an effort than spanned more than thirty years, this group spearheaded and helped complete the Pumpkinvine Trail, which with several other trails now connects Goshen, Middlebury, and Shipshewana. They continue to work on trails, especially in Elkhart County.
As of 2025, this Muncie-based land trust has 18 preserves and protects nearly three thousand acres. They focus on five counties in east-central Indiana.
Cooper Audubon is a Muncie-based chapter of the National Audubon Society. They host monthly meetings and lead periodic field trips, as well as engaging in conservation and education projects.
Sassafras is a local chapter of the National Audubon Society, based in Bloomington, but serving members in eight counties. They host periodic meetings, sponsor field trips, and engage in various bird and conservation related activities. Of special note is their sponsorship of Indiana's first northern saw-whet owl banding station. (Hat tip to Ross Brittain)
One of the early giants of the Indiana conservation movement, officially formed in 1952 but with roots that go back much further. Their focus is on preserving, protecting, and restoring the Indiana dunes.
The Shirley Heinze Land Trust works in six northwestern Indiana counties and has (to date) protected more than 4,000 acres of natural areas. Many of those places have trail systems that are open to the public.
John Muir founded the Sierra Club in 1892, and though its initial emphasis was on the mountains for which it was named, the organization now spans the entire countries and includes 8,000 members right here in Indiana. The Hoosier Chapter covers the entire state, and there are local groups based in Bloomington, Columbus, Evansville, and Indianapolis.
South Bend-Elkhart Bird Alliance
A local chapter of the National Audubon Society that hosts periodic meetings and field trips. They also maintain a 35-acre sanctuary in Mishawaka.
Another local chapter of the National Audubon Society, this one with members in six counties centered around the Lafayette area. They host regular meetings and field trips, and SAS members were instrumental in founding
Bloomington-based Sycamore protects more than 140 properties comprising more than 11,000 acres across southwestern Indiana. More than a dozen of their preserves have hiking trails and are open to the public.
TAS is a local chapter of the National Audubon Society whose members reside in eight north central Indiana counties. Along with hosting regular meetings and field trips, they also own and manage three nature preserves in northeast Wabash County, all of which are open to the public.
Valley Watch has been working to protect public health and environment of the lower Ohio River Valley since 1981, with a focus on preventing polluting industries from locating in the area, and reduce the emissions of existing industries.
A chapter of the National Audubon Society based in Terre Haute. Its members reside in five western Indiana counties.
Wawasee Area Conservancy Foundation
A local organization focused on protecting, preserving, and enhancing the Wawasee Area Watershed.
Wesselman is based in Evansville and responsible for the management and daily operations of the incredible Wesselman Woods Nature Preserve, a 200-acre old growth forest that is the largest of its kind within any city limits in the United States. It is also responsible for Howell Wetlands on the west side of the city.
An alliance of diverse interests and organizations that work together across 16 counties to steward the White River and its watershed.
White River Watchers of Madison County
Works to protect the White River and its ecosystem in Madison County.
Wildcat Guardians work to protect and conserve the environment, with an emphasis on protection of Wildcat Creek, which drains about a half million acres in north central Indiana. They meet monthly in Kokomo.
Wolf Park operates more than one hundred acres of rewilded farmland that provides a permanent home to wolves, bison, foxes, and other native species and serves to foster connections between people and wildlife.