The river headwaters emanate from Farringtons Pond (New York border with
Danbury, Connecticut. It meanders through
Sanfords Pond ( ) and
Lake Kenosia ( ) before entering a concrete aqueduct near
downtown Danbury. It then turns north and becomes a more conventional river as it cuts through
Brookfield and southern
New Milford before joining with the Housatonic (
STILL RIVER (HOUSATONIC RIVER) Latitude and Longitude:
). It has a drainage area of 85 square miles, and a mean flow of 377 cubic feet per second. 
Mercury nitrate was discharged to the river by the hatting industry from circa 1860 through the first half of the 1900s. The hat factories used the chemical in the felt making process to remove animal fur from pelts.   Along the river, levels of mercury are found to be 5-10 ppm with extremes up to 100 ppm, levels about 500 times higher than background levels.    The P. Robinson Fur Cutting Company was one fur removal company sited on the Still River. Mercury pollution has transported with the river's current into the Housatonic River, and into the Long Island Sound. 
The river was essentially dead in the 1980s, but after Danbury constructed a new sewage treatment plant in 1993 the river rebounded. Many species of fish can now be found, and kayak ramps have been installed downriver from Danbury.[ citation needed]
At least three organizations have an interest in preserving the Still River and its watershed. Spearheaded by Danbury's Health Department, the Still River Alliance was organized in 1995 as a consortium of three different groups. The Alliance developed a website (see external links below) which has not been updated for several years. Due to budget cuts, the driving force behind the Alliance, Jack Kozuchowski, retired and the Still River Alliance seems to have floundered since then. Mr. Kozuchowski is currently an environmental consultant.[ citation needed] Coordinated by the Housatonic Valley Association and with funding from Connecticut Department of Energy and Environmental Protection, key stakeholders and municipalities formed the Still River Partners group and launched an EPA approved watershed planning process to improve the water quality of the Still River which is still active today.
The Housatonic Valley Economic Development Partnership is striving to develop a 38-mile (61 km) River Trail on the Still and Housatonic rivers for canoeing and kayaking. They periodically organize river clean-ups, using paid contractors and volunteers, to clear debris from the river. They also lobby for kayak put-in/out ramps. The beginning of the trail is located behind the Marriott Courtyard hotel, just off of Route 84 (Exit 8) in Danbury. Rapids interrupt the river trail in Brookfield (no portage is available), and three dams across the Housatonic require portages along the way to Long Island Sound. 
The Still River Preserve in Brookfield covers about 80 acres (32 ha) adjacent to the river. The preserve is owned by Weantinoge Heritage Land Trust of New Milford, Connecticut.
The city of Danbury has a $4.85 million bonding package, approved in a February 2008 referendum, for use in building recreational projects on city-owned land. A list of potential projects was prepared. It includes completing the native plant hedgerow at Lake Kenosia (part of the Still River, west of the city) and doing a feasibility study to build a boardwalk and bird-watching site on about 20 acres (8.1 ha) the city owns in Mill Plain Swamp (Lake Kenosia discharges into the swamp, which drains into the Still River). A separate $6.6 million bonding package, approved in the same referendum, could be used to purchase Sanford's Pond and building a trail through it.[ citation needed]
- U.S. Geological Survey. National Hydrography Dataset high-resolution flowline data. The National Map Archived 2012-04-05 at WebCite, accessed April 1, 2011
- Bronsther, Rachel; Welsh, Patrick. Mercury in Soils and Sediments. Wesleyan University. Retrieved 30 September 2015.
- Lerman-Sinkoff, Sarah (April 2014). "Transport and Fate of Historic Mercury Pollution from Danbury, CT through the Still and Housatonic Rivers". Middletown, CT: Wesleyan University. Bachelor of Arts thesis.
- Varekamp, Johan (2002-06-25). "'Mad Hatters' Long Gone, But The Mercury Lingers On". UniSci. Cape Coral, FL: UniScience News Net, Inc.
- Varekamp, JC; Buchholtz ten Brink, MR; Mecray, EL; Kreulen, B (Summer 2000). "Mercury in Long Island Sound Sediments". Journal of Coastal Research. 16 (3): 613–626. JSTOR 4300074.
- The dams include the Shepaug Dam that impounds Lake Lillinonah, the Stevenson Dam Hydroelectric Plant that impounds Lake Zoar, and the Derby Dam between Derby and Shelton that impounds Lake Housatonic.