Washington Trust Executive Director Chris Moore (center) and other block party attendees raise a cupcake to the Stimson-Green Mansion’s 125th birthday. Photo courtesy of Kanan Gole Photography.

Picture this: A bright red bouncy house next to an Tudor Revival mansion, a wine garden beside decades-old camellias, and colorful leaf printing crafts in the shade of trees planted more than a century ago. This was the blend of the past and the present celebrated at the Stimson-Green Mansion Birthday Block Party on Saturday, June 13!

This year, 2026, the Stimson-Green Mansion turned 125 years old. One of the first buildings erected in the historic First Hill neighborhood, the Mansion has lived a long and storied life. It was built by the Stimson family in 1901 and later purchased by the Green family, two of Seattle’s “founding families.” After being places on the National Register of Historic Places by Historic Seattle, the building became home to a catering company founded by the Stimsons’ granddaughter. Today, this historic gem serves as the headquarters of the Washington Trust for Historic Preservation and its community event program.

Celebrating such a milestone for such an important historic building required a party of the proper magnitude. So to celebrate, we pulled out all the stops. Learn more about this community birthday party below!

All the fun that was had at the Stimson-Green Mansion 125th Birthday Block Party on June 13, 2026: a bouncy house, pet portraits, giant Jenga, crafts, and putt putt. Photos courtesy of Kanan Gole Photography.

Organized by the Washington Trust for Historic Preservation and the First Hill Improvement Association, this event closed down a block of Minor Avenue—the street right in front of the historic home—and took over First Hill Park. In the street, we brought in food trucks, yard games, and crafts. We spread out eight holes of pop-up putt putt golf in First Hill Park. For the pet lovers in the neighborhood, we also had a watercolor artist painting portraits of guests’ pets, featuring a custom border designed based on elements of the Mansion itself. And of course, we offered tours of this historic house.

To really harness the block party vibes, we hosted live performances on a “stage” set up right on Minor Avenue. Swing dance lessons, sea shanty singalongs, street bingo, outdoor yoga, and a rousing rendition of “Happy Birthday” by the Seattle First Baptist Church choir filled the street with laughter and joy.

Other local community and cultural organizations joined us in the street all party long. We were thrilled to have tables set up by Humanities Washington, the Freeway Park Association, the Frye Art Museum, &Fitness, DRYFT Music, Salal Cred Union, and the First Hill Improvement Association. Some of these organizations are based right here in First Hill, while others regularly host events for the local neighborhood. They all brought something special to the block party, from collaging activities by the Frye Art Museum to leaf printing with leaves from the Mansion’s garden.

Attendees enjoy the beautiful day and engaging activities at the Stimson-Green Mansion 125th Birthday Block Party on June 13, 2026. Photos courtesy of Kanan Gole Photography.

And the people came out! Guests of all ages bounced in the bouncy house and competed in putt putt golf tournaments. They challenged each other to giant Jenga and cornhole on the Mansion lawn. Pets of all sizes strolled the block, many of whom had their portrait painted.

Guests joined us from across the region, as far away as Everett and Centralia to as nearby as the apartment across the street. Over the course of our four-hour event, we had more than 500 people join us in celebrating. Mansion tours were packed to the gills with around 40 people each hour. More than 60 pets had their portraits painted. At the end of the event, we handed out 250 mini cupcakes to guests who raised them up to the Mansion in a toast as we sang “Happy Birthday.”

We are so grateful to everyone who joined us for this incredible event! It was truly a special way to celebrate the Stimson-Green Mansion and this neighborhood it has called home for 125 years.

Attendees enjoy the Stimson-Green Mansion 125th Birthday Block Party. Photos courtesy of Kanan Gole Photography.

A special thank you to the City of Seattle’s Department of Neighborhoods, 4Culture, and Salal Credit Union for their generous support of this event!