Mercer County (1974–present)

Between 1975 and 1984 the farm was prepared by the Mercer County Park Commission, assisted by volunteers who later organized as the Friends of Howell Farm, for opening to the public as a living history farm. The milk house built by the Tylers for their dairy goat operation was demolished and the interior was reconfigured to meet the needs of interpreting farming in the period 1890-1910. During this decade, buildings were stabilized, a collection of farm equipment was gathered, a survey of the barn structure was completed, and preliminary plans for barn preservation were drawn up.

On December 1, 1976 the Farm was listed on the New Jersey State Register of Historic Places.

On May 2, 1977 the Farm was listed on the National Register of Historic Places.

In 1978 the Friends of Howell Farm was incorporated as a non-profit group to assist the Mercer County Park Commission with planning for and operating the Farm.

In 1980 Howell Living History Farm became a member of the Association for Living History, Farm, and Agricultural Museums (ALHFAM). Also in 1980 the Osage orange hedgerow along Valley Road was reestablished. A mid-19th century wagon house was moved to the Farm from the former Tindall farm in West Windsor, New Jersey. In 1983 this became the Farm's sheep barn.

On June 9, 1984 Howell Living History Farm was opened to the public on to provide visitors with experiences of life on an 1890-1910 family farm of the region.

In 1985, in its first full year of operations, Howell Farm hosted 21,500 visitors. One third of the visitors were schoolchildren who were able to participate in hands-on farming activities. During this year, the farm orchard was re-established in its original location along Hunter Road in memory of William Mount of Princeton.

Between 1985 and 1990 the full-range of historically accurate tillage, planting, harvesting and processing operations were established at the Farm.

In 1987 the Farm received state and national attention when staff and interns assisted New Jersey Governor Tom Kean in breaking ground for the New Jersey Museum of Agriculture using an Angus steer Kean won in a bet on Super Bowl XXI. This steer continued to receive training as an ox and lived out his life on the Farm, where he was known as Giant.

In the 1990s restoration plans for the barn were completed, preliminary projects such as asbestos removal were carried out, and fund raising began.

In 1991 the ice house was restored by volunteers with funding from the Friends of Howell Farm. A memorial stone was dedicated in memory of the donors of the Farm, Charles and Inez Howell. The Pleasant Valley Rural Historic District, of which the Farm is a keystone, was formed and listed on the New Jersey and National Registers of Historic Places.

In 1993 the Farm played host to a regional conference of the Mid-Atlantic Association of Living History, Farm and Agricultural Museums (MAALHFAM).

During 1994, in the 10th year of public operation, 45,000 people visit the farm, including 11,000 school children. 11,220 hours of work towards farming, programming and restoration projects are contributed by volunteers.

In 1995 the annual ice harvest made the cover story for New Jersey Outdoors' winter issue. The ice was 13 inches thick and was thick enough to allow one of the draft horses to be used in cutting the ice. The Institute of Museum Services (IMS) awarded the farm a grant to assess its collections. The first Howell Farm website was created by volunteer Dana Kruser.

In 1996 four acres along Hunter Road were purchased by Mercer County from Lowell Hunter. These acres had once been part of the farm but were sold to Hunter's father in 1905. The New Jersey Historical Commission awarded the Farm a grant to document 25 horse drawn farming operations.

In 1997 fund raising towards restoration of the Henry Phillips Barn was augmented with the creation of a four-acre cornfield maze with the help of the American Maze Company. The maze design depicted the Henry Phillips Barn. This project helped the Friends of the Farm raise $27,400 to be used towards the barn restoration. The maze has become an annual event and has since risen over $350,000.

In 1998 volunteers constructed a new chicken house whose design is representative of the farm's time period. Funding was provided by a grant from the New Jersey State Poultry Association.

In 1999 funding for a 5,000 square-foot Visitor's Center was approved by Mercer County and a design was created by the Princeton architectural firm CUH2A. Membership in the Friends of Howell Farm rose to 350. In November the Farm hosted its second regional MAALHFAM conference. This conference focused on barn restoration and was a kick-off event for the restoration of the Henry Phillips Barn. A focal point of the conference was the raising of a small barn just north of the Henry Phillips Barn. This small barn was needed to provide a home for the Farm's oxen, their equipment, and food since they would be displaced by the barn restoration.

In 2000 volunteer Larry Kidder created a new website for the Farm that features a virtual tour of the Pleasant Valley Rural Historic District. Longtime volunteer and former member of the trustees of the Friends of the Farm, Dorothy Washburn, was hired as curator with a matching grant from the New Jersey Historical Commission. A Grant from the Garden State Historic Preservation Trust Fund of $28,000 was received to begin work on a new master plan for the Farm.

In 2001 the Kleio Club of Pennington presented the Farm with a check for $10,000 in memory of club member Jean Errickson, as a contribution towards restoration of the Henry Phillips Barn. Restoration of the Henry Phillips Barn began on April 7 when restoration mason Tom Livingston began work on foundation repointing. On May 9 ground was broken for the visitor center by County Executive Robert D. Prunetti using a Deere-Syracuse walking plow pulled by workhorses Blaze and Frank. On June 8, Howell Farm oxen Bud and Jake moved into their new quarters in the small barn raised in 1999.

In 2002 the 15 acre Birum property adjoining Howell Farm was acquired by Mercer County.

On April 24, 2003 the ribbon was cut by Mercer County Executive Robert D. Prunetti to officially open the new visitor center. In June the Farm, along with four other New Jersey historic sites, was host for the 32nd Annual Meeting and Conference of the Association for Living History, Farm and Agricultural Museums (ALHFAM). Also in 2003 Mercer County acquired 35 acres from Joe Tesauro, land formerly part of the Smith Farm across Valley Road from Howell Farm.

In 2004 Mercer County acquired the former Pleasant Valley school house at the corner of Hunter Road and Pleasant Valley Road.

On May 14, 2005 the historic Charles Fish Barn was raised during a public program with the assistance of the New Jersey Barn Company. This barn is now part of the visitor center.