BELFAST – Abraham Lincoln was still practicing law and this city on the Passagassawaukeag River was only a year old when Spencer Wolcott Mathews opened his sawmill here in 1854.

One hundred fifty years later, Mathews Brothers is keeping well, thank you, with more than 100 employees and a retail presence in Bangor and Rockland as well as Belfast.

Maine’s oldest window manufacturer celebrated its 150th birthday Wednesday with an outdoor barbecue and ceremony honoring its employees, customers and suppliers.

“From ‘Little Home on the Prairie’ to Home Depot,” said Mayor Michael Hurley during the ceremony. “It’s an amazing testimony for an amazing track record of 150 years.”

Soon after Mathews went into business, he was joined by his brothers, Noah and Sanford, and the company’s name was changed to Mathews Brothers. The family continued to operate its milling business, making window frames and other wood products for customers throughout New England.

That is still the case as the firm’s customers range from Fort Kent in the north to Cape Cod south and west to New York’s Hudson River Valley, said company President Scott Hawthorne.

“It’s the same distance from Belfast to Fort Kent-Madawaska as it is from Belfast to Cape Cod,” he said. “It’s a lot of territory.”

After the turn of the 20th century, O.E. Frost assumed ownership, and the company diversified into such things as spiral stairs and even caskets. In 1919, Mathews Brothers completed what was perhaps its most unusual contract, construction of the five-masted schooner Jennie Flood Kreger. Through it all, the mainstay was windows.

Hawthorne said that is still the case, though the company recently added patio doors to its popular line of windows.

Besides its manufacturing facility in a sprawling complex on the city’s outskirts, the company also has retail stores in Belfast, Bangor and Rockland, offering windows, doors and kitchen components.

In keeping with its heritage, Mathews is one of only a handful of manufacturers continuing to build solid wood, double-hung windows with true divided lights.

Hawthorne said the company has managed to stay ahead of its competitors by insisting on quality control and rapid delivery. He said the company has to work harder to hold its position in the marketplace and confront a global economy.

“We’ve withstood it so far because the Chinese haven’t caught up to us yet. Every show we go to, the Chinese are there,” Hawthorne said. “They are very good at mass production, so we have to concentrate on getting our products to the consumers sooner. If you can offer enough unique products, it makes it that much more difficult for them to keep pace. We think we’ve taken the steps to stay fully involved in the industry.”

Along with city officials, the company also received congratulatory letters from Gov. John Baldacci, Sens. Olympia Snowe and Susan Collins, and others.