For 30 years, Jane Sween was the librarian for the Montgomery County Historical Society. The society's Rockville library is named after her. (John Kelly/The Washington Post)

The first question out of Answer Man’s mouth when he arrived at the Jane C. Sween Library in downtown Rockville was: “Who was Jane C. Sween, anyway?” The answer was unexpected.

That’s Jane Sween,” said librarian Pat Andersen.

A handsome older woman rose from her work and confessed that she’s happy the honor wasn’t bestowed upon her posthumously.

Housed in a converted garage building, the library named in honor of Jane holds the research collection of the Montgomery County Historical Society, which is headquartered nearby and operates the adjacent Beall-Dawson House.

That’s “Beall” as in “bell,” which is how that branch of the family pronounces it, Jane said. Others pronounce it “beal.”

“There’s a Beall Elementary School on Beall Avenue,” said Jane, alternating the pronunciations. “Make sense of that one.”

The library is where visitors can make sense of county history. Unlike the local history operations in the District or Fairfax County — where each collection is part of the library system — Montgomery’s is run by the nonprofit historical society. Access is free to members and $5 for visitors ($3 for students and seniors).

What will you find there? Well, on Wednesdays and Thursdays, you’ll find Jane. She was the society’s librarian for 30 years until 1998. She also wrote “Montgomery County: Two Centuries of Change.” Jane says the subtitle sums up Montgomery County, which has been transformed over the decades.

About half the library’s visitors come to work on genealogies, said Pat, who’s been the librarian since Jane’s retirement. They find ample resources, including clipping files on some 1,000 families whose histories are wrapped up in the county’s. They range from the Allnutts to the Zimmermans and include such familiar names as King, Magruder, Prather and Offutt. The first Friday of every month, volunteers help solve genealogical problems, whether they involve the county or not.

Volunteers are a big part of the operation. On the day Answer Man stopped by, Ellie Hagner of Rockville was helping Jane sort through boxes of photos and documents donated by the family of Neal Potter, the late county executive.

Upstairs, where the special collections are housed, are the papers of the Montgomery Mutual insurance company. Policies are arranged in chronological order. The oldest one, from March 30, 1850, is for the buildings onFrancis Preston Blair’s estate, which was called “Silver Spring” before there was a Silver Spring. (It was the flecks of glittery mica in a nearby watering hole that inspired the name.)

There are yearbooks from schools that are still around (Richard Montgomery, Churchill) and ones that aren’t (the National Park Seminary, whose 1920s annuals show what the girls got up to). There’s also a set of neatly bound copies of the Pepconian from 1946 to 1970. The Pepconian? That’s Pepco’s employee newsletter.

There are 5,000 books in the library’s collection, ranging from compilations of early landholders to the histories of such county-based endeavors as White Oak Labs, where naval ordnance was developed. There’s plenty on the Civil War and War of 1812, too. Defunct newspapers — the Bethesda Advertiser, the Bethesda Tribune, the Bethesda Journal — are available in bound copies or on microfilm. Such obscure material as swim club records, PTA mailings and the papers of the Falkland Chase apartments await the right researcher.

The library once stored the rope from the last hanging in Montgomery, used in 1921 to dispatch Guy Vernon Thompson, who blew up James Bolton and his housekeeper’s two children with dynamite. The rope is now in the historical society, although Thompson’s story is told along with those of other ne’er-do-wells in library files marked “Crime.” (The headline of one story about Thompson reads: “Goes to Gallows in Fearless Mood.” The copy of his death certificate in the file says he died from “dislocation of neck.”)

Of course, the best parts of any local history library are not on the shelves or in the files but between the ears: the brains and memories of librarians and volunteers such as Pat, Jane and Ellie.

Visit or get in touch

Jane C. Sween Library — 42 W. Middle Lane, Rockville. Open 10 to 4 Wednesday to Friday, noon to 4 Saturdays. Admission free to Montgomery County Historical Society members, $5 for nonmembers, $3 for students and seniors. Call 301-340-2974, e-mail librarian@montgomeryhistory. org or visit www.montgomery

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