SELAH, Wash. — As he stood near a granite monument along North Wenas Road, writer Jo N. Miles looked out over a rich valley that has attracted humans for centuries.

Some came here to hunt and cultivate crops, like countless ancestors before them. Some passed through to pave the way for others who sought new opportunities for themselves and their children.

The 5-foot-tall stone slab commemorates three groups of people — Native American Chief Ow-Hi and his family, who lived and farmed here; the first emigrant wagon train from the East that camped here, named for its leader, James Longmire; and Capt. George B. McClellan and his soldiers, who unfurled the American flag for the first time in Yakima County in August 1853.

But while it doesn’t say as much, the well-kept monument near a bend in the road about 3 miles northwest of Selah also commemorates something else — the founding of the Yakima Valley Historical Society on Sept. 20, 1917, the same day the granite slab was dedicated.

“It’s a triple commemoration,” Miles said of the stone erected by the Yakima Pioneers Association. “Happily it coincided with this other dedication that happened 100 years ago.”

The historical society celebrates its 100th anniversary Sunday during its regular monthly meeting at the Yakima Valley Museum in Yakima. The meeting will include a free public program by Miles at 2 p.m.

“We want to celebrate Ow-Hi and the monument that was dedicated on the 20th,” said Paul Schafer, historical society president.

The monument stands about 2 miles south of the North Wenas Road-Longmire Road junction and about a mile from where David Longmire lived. John Longmire’s son was 9 when the wagon train passed through the Wenas Valley on its way to the West Coast. His family settled in an area near Mount Rainier known as Longmire.

“David remembered this valley. When he reached adulthood, he came back to the Wenas Valley,” Miles said.

As president of the Yakima Pioneers Association, David Longmire presented the memorial during its dedication on Sept. 20, 1917, and then appointed committee members “to organize a local historical or memorial society,” according to meeting minutes.

The new historical society’s first meeting took place in the Miller Building in Yakima on Oct. 3, 1917, with the first by-laws meeting about a month later.

“It was then determined that the principal sphere of the society’s particular activities shall be that country which was the home of the (Yakama) Indians when the first white man came here, being more particularly the Yakima (River) water shed,” note the minutes of the Nov. 7, 1917, meeting.

“They actually named two tribal members as their first honorary members,” Miles said of Chief Ow-hi Saluskin and Capt. Billy Holite.

The entire valley along Wenas Creek was a significant home of Ow-Hi — a traditional dwelling place where he and others grew their own produce, Miles said. “(McClellan) wrote of seeing significant fields of potatoes, melons and corn,” he added.

The Longmire wagon train arrived at Ow-Hi’s gardens three weeks later.

“They were desperate for fresh produce,” Miles said; they purchased several bushels of potatoes from Ow-Hi to supplement the beef they had eaten almost exclusively since their journey began.

Local tribes had learned how to cultivate crops from Hudson’s Bay Co. employees, Miles said.

“During my research, I found that (Chief) Kamiakin and his brothers had fields and fields of corn and were raising cattle,” said Miles, author of “Kamiakin Country: Washington Territory in Turmoil 1855-1858.” Ow-Hi was related to Chief Kamiakin.

Despite its 100 years, the monument looks good — new, even.

“Somebody’s taking care of it,” Miles said.