Earle Shettleworth Jr., who has served longer than any state preservation officer in the country, is retiring as director of the Maine Historic Preservation Commission on Oct. 1.

“Frankly, I looked at the numbers and I realized I was going to be 67 in August, and in September I will have worked 42 years for the state,” Shettleworth said in a telephone interview Tuesday after the commission announced his retirement. “While I have thoroughly enjoyed every moment of that, by the same token, it was a really good time to embark on concentrating on the things I most enjoy.”

Shettleworth started with the commission in 1973, was named acting director two years later and has led the agency ever since. During his administration, the commission has nominated 1,592 Maine properties to the National Register of Historic Places.

Shettleworth will continue in his post as Maine’s state historian. Among his first tasks in retirement will be organizing the commission’s files of photographs, illustrations and documents related to Maine’s human-built environment. In December, Gov. Paul LePage reappointed Shettleworth to a third four-year term in that post.

Shettleworth is known for his love of Maine history, his knowledge of art and architecture, and his commitment to preservation. As a teenager he was among the founders of Greater Portland Landmarks, and helped lead efforts in Portland and around Maine to preserve cultural landmarks.

“Maine is looked at as a model in its historic preservation activities, and Earle is admired around the country for what he has accomplished up here in terms of guiding the state in those activities,” said Thomas B. Johnson, chair of the state preservation commission and director of the Victoria Mansion in Portland.

He called Tuesday’s announcement “seismic. It’s a major event in preservation and cultural circles.”

PASSION FOR ART AND ARCHITECTURE

Shettleworth grew up in Portland, and graduated from Deering High School in 1966. His interest in history began when Portland’s Union Station was demolished in 1961. He was 13 at the time. He studied art history at Colby College in Waterville and earned a master’s degree in architectural history from Boston University.

Nearly all of his work since then has involved his interest in art and architecture in Portland and across Maine. His passion for those subjects has never waned, he said Tuesday.

“I think what has sustained my interest, No. 1, is that no one day is like another,” he said. “There are always new challenges as far as the administrative part of the work is concerned. But in addition to that, I’ve always looked upon the job as a tremendous lifelong learning opportunity.”

As an example, he cited his work a few years ago leading up to the 150th anniversary of the Civil War. As part of his research, he visited and documented every Civil War monument that he was aware of in Maine – 148 in all, from York to Aroostook counties. He photographed the monuments and copied the inscriptions. He later learned of a few he missed.

“To me, that was just such a wonderful opportunity to focus, and at the same time to visually review Maine as a whole from a historical and architectural standpoint,” he said.

Shettleworth will be replaced by Kirk F. Mohney, the agency’s assistant director. Mohney joined the commission in 1986 as coordinator of the National Register of Historic Places and architectural survey programs. He became assistant director in 2001. Hiring a long-tenured employee from within the agency should help ensure a smooth transition, Johnson said.

The primary function of the preservation commission is to identify, evaluate and protect Maine’s cultural resources.

DEEP KNOWLEDGE OF MAINE CULTURE

Reaction to Shettleworth’s retirement was swift among Maine’s cultural leaders.

“He’s an unexpected rock star,” said Hilary Bassett, executive director of Greater Portland Landmarks. “He embodies historic preservation in Portland and in Maine.”

Two weeks ago, Shettleworth delivered a lecture about historic postcards that drew a capacity crowd to a University of Southern Maine lecture hall. “That’s pretty impressive,” Bassett said.

As a board member at Maine College of Art, Andres Verzosa nominated Shettleworth for an Art Honors award, conferred by the Portland art school. A former Portland gallery owner, Verzosa worked with Shettleworth on several projects, admired his dedication and knowledge, and viewed him as a role model for working in the arts while improving the quality of life for his community.

Fittingly, they met when Verzosa was working in a Portland antiques store and Shettleworth came in to purchase vintage photographs of Monhegan Island by Henry Levy.

Later, Verzosa was helping Portland photographer Rose Marasco place her Maine Grange series in museum collections statewide, and he asked Shettleworth for assistance. Shettleworth helped place more than 100 black-and-white photographs of Grange exteriors and a lesser number of related photographs into the State of Maine collection.

“He’s a state treasure,” Verzosa said. “He’s one of those people whose institutional knowledge and breadth and depth of information about the culture of Maine is unsurpassed. He is very humble and thoughtful, and he has dedicated his life to Maine. That’s very rare.”

YEARS OF SERVICE ‘NOT DONE YET’

Through his work as state historian and his independent scholarship, Shettleworth plans to continue to study and interpret Maine history. On Wednesday, he is delivering a lecture at the University of New England in Portland about the paintings of John Calvin Stevens, Portland’s best-known architect. This summer, he will lecture about the photographer George Daniell at the Ogunquit Museum of American Art.

He has many projects in the works that will keep him busy for years, he said.

“I’m grateful for this privilege of working for the state and serving the people of Maine,” he said. “It has been a lifelong effort, and I’m not done yet.”