NE Soil
- Featuring soil information by county, ground penetrating radar, GIS, and soil profile photos.
- http://nesoil.com/

Amateur Telescope Makers of Boston (ATMoB)
- Club supporting observation, star parties, telescope design/building/improvement and astro-photography.
- http://atmob.org/

Charles River Natural Valley Storage Area
- Includes flood control, recreation, and preservation information.
- http://www.nae.usace.army.mil/recreati/crn/crnhome.htm

Assabet River Rail Trail
- Non-profit organization to create, promote, and help maintain a multi-purpose recreational trail through the communities of Marlborough, Hudson, Stow, Maynard, and Acton.
- http://www.arrtinc.org/

Organization for the Assabet River
- Works to preserve and protect the health and beauty of the Assabet River and its watershed.
- http://www.assabetriver.org/

Eastern Massachusetts Hawk Watch
- Information on where are the best hawk sighting locations, how to report a sighting and volunteering for the organization.
- http://massbird.org/EMHW/