With an estimated 2014 head count of 249,109, and an average annual growth rate of 2,750 people so far this decade, the county almost certainly has hit the mark already.

It’s a moment to glance back at more than a century and a half of growth, decline and boom times, phase by phase. So here’s a quick narrative version of the squiggles you see on the chart on this page.

1850-1914: Boom No. 1

Viewed from the heights of 250,000, the county’s early growth looks downright glacial. It took a full century to add as many people as would later flood in during a pair of decades.

“The early years were boom times for the county,” said Brent Peterson, director of the Washington County Historical Society. “A huge percentage of all those living in the entire state were right here in Washington County.”

Indeed: Nearly 1 in 5 people as of 1850, though that figure would shrivel to the 1 percent to 4 percent range over time.

On Aug. 24, 1839, in Marine on St. Croix, the Marine Lumber Company “cut its first pine log and became the first commercial sawmill in what was to become the State of Minnesota,” reports the Minnesota Historical Society, which owns the site’s ruins today.

Soon steam-powered sawmills all along the St. Croix River were sending valuable lumber elsewhere, and farmers profited from feeding the logging teams. Population quintupled in the 1850s, doubled again in the 1860s, then grew at slower rates until it went into decline.

1914-1930: End of Boom 1

The year 1914 was “a watershed for Stillwater in particular” as the county’s fortunes were being reversed, Peterson said.

“The lumber was getting logged out. The industry was dying. People were moving west, companies moved west, lumbermen moved west, and some lumber barons died that same year.”

The decades of the 1900s and the 1910s were the only years the county has ever experienced outright drops in population, though growth remained feeble in the ’20s and ’30s as well, with just a trickle of new arrivals compared to what was to happen soon.

Still, the iconic Lowell Inn opened in Stillwater in 1927 and, in 1931, a new Lift Bridge. Highways were getting built, and the Andersen Company in Bayport had 340 people on its payroll in 1936.

But a major shift in the county’s center of gravity was about to take place.

1930-present: The ’Burbs

“Up till around 1950,” said Marc Hugunin, of Grant, author of the suburbanization section of the historical society’s standard history book, “probably half to two-thirds of our population was still on the east side: Stillwater, Scandia, Afton, Bayport, all those places that don’t seem as significant today as they did then.

“Today probably two-thirds to three-quarters are on the west side, and the most significant thing that really caused that was the freeways.”

The biggest jump in the county’s population, equaling its entire first century, happened in the 1990s, notably in Woodbury: 55,000 people either moved in or were born. But historians say it’s just as important to recall the role of Cottage Grove as an early staging ground in the 1950s for the Orrin Thompson firm, which would go on to create so much of Twin Cities suburbia. And 3M arrives in the 1950s, adding a 14-story headquarters in Maplewood in 1963 that accelerates growth all around.

“Cottage Grove gets going around the same time as Richfield and Roseville,” Hugunin said, “but while they grow out border to border, Cottage Grove doesn’t. As freeways come along, development shifts to Woodbury: in terms of highway access, why would you live in Cottage Grove when there’s a Woodbury?

“It’s all about transportation: People who live in Eden Prairie live there because it’s close to a job, but people don’t live in Washington County for that reason, because it’s not close to a job.”