The Arc of York and Adams Counties officially opened its doors on October 14, 1952, becoming the 137th chapter of The Arc of the United States. Since that day, The Arc of York and Adams Counties has been representing the rights and interests of all people with intellectual disabilities, regardless of their age, functional levels, behavioral levels, or geographic location within York and Adams Counties.

1952 - Incorporated as "Association for Retarded Children"

1953 - Opens first day care center at St. Mark's Lutheran Church which then moves to 929 W Market St.

1954 - Formation of Adult Recreation Club and Day Camp

1962 - Camp Pennwood formally opens

1965 - The Arc of York County moves programs to the JFK Memorial Training Center in York

1965 - The new game "Tether Ball" is introduced to camp, screen doors and cement pads are installed

1968 - Overnight cabin built at Camp Pennwood to expand camp program

1969 - Camp Pennwood roof collapses causing $25,000 worth of damage. Within one year the building was fixed through donations of time and money.

1972 - First "Bike and Hike" fundraising event

1973 - Name changes to "Association for Retarded Citizens" and advocacy program begins

1974 - The Arts and Crafts building is added as a new facility at camp and the following year carpet is installed in the lodge

1982/83 - Client and Family Services Program is formalized and along with Camp Pennwood, services to clients are increased

1984 - After-School program established as first latch-key program in PA for teens with intellectual disabilities

1987 - "Penn Employment Services" is established to place, train, and support adults with disabilities

1993 - The ARC changes its name to "The Arc of York County"

1994 - The After School program moves to the YMCA of York

1995 - The Arc Foundation is established

1997 - The Arc opens the "Rainbow's Arc Child Care Center" at the Haymeadow building in York

2001 - The Arc sells the "Rainbow's Arc Child Care Center"

2001 - The Arc moves to its new home on 497 Hill Street in York

2002 - The Arc's "After School" program moves to the Otterbein United Methodist Church in York

2010 - The Arc's first "10 Miler Race" fundraising event

2011 - The Arc of York County takes on the new national logo

2015 - The Arc's "After School" program moves to Luther Memorial Church in York
2018 - The Arc of York County holds its first ever "The Arc Ball and Auction"
2019 - Thanks to a grant from the J. William Warehime Foundation, The Arc of York County added a ramp to the front entrance of the Hill Street facility and made renovations to their reception area.
2021 -  The Arc of York County opens the "Highland Center for Vocational Services" in West York.  The new center houses its Penn Employment Services staff.
2022 - The Arc of York County and The Arc of Adams County make the decision to merge, creating "The Arc of York and Adams Counties." 
2023 - The Gettysburg Center opens at 14 Deatrick Drive in Gettysburg.