The Lower Merion Conservancy was formed in September 1995, when the Lower Merion-Narberth Watershed Association merged into the Lower Merion Preservation Trust, and organizations joined forces as the new Lower Merion Conservancy.
Over the years, LMNWA built stream bank improvement projects in a variety of locales, like Harriton House and West Mill Creek Park, planted trout eggs, monitored stream chemistry and more.
The Lower Merion Preservation Trust was formed in 1991, the outgrowth of a Lower Merion Township study on disappearing open spaces. LMPT organized to advocate for the preservation of landscapes and community character, and grew to embrace protection of historic resources as well. The trust invested extensive energy in contacting owners of large properties, arranging for these properties to be set aside in perpetuity.
In 1994, these efforts bore fruit, when Lower Merion Township agreed to purchase the former Walter C. Pew estate in Gladwyne, a 103-acre property now called Rolling Hill Park.
In 1997 the Conservancy decided to raise funds to restore the 1895 caretaker's cottage at Rolling Hill Park. The cottage, completely restored by May 2000, now serves as the headquarters of the Conservancy.