At the midpoint of the 20th century, Clayton and Henry were farming communities.

As the 21st century dawned, both counties were bursting with growth from the arrival of new and diverse populations, attracted by the transformation of Atlanta during the last three decades from just another midsized Southern town into an international gateway.

Highlighting the continuation of that transformation, two major projects in Clayton were in full swing at the beginning of 2003:

• Construction of a 9,000-foot fifth runway at Hartsfield International Airport on the county's north end that will cross Atlanta's perimeter highway, I-285. Planes will actually land and take off on a bridge that will span I-285. Planners hope to complete work in 2005.

• Building a new Southeast region headquarters for the National Archives and Records Administration. The federal archives will be on the same site as the new State Archives, which became ready for occupancy this spring. The two archives, located next to Clayton College & State University, which stretches across Lake City and Morrow, are expected to be the catalyst for a hotel, restaurants and potentially a golf course in the area along Jonesboro Road.

Meanwhile, in Henry County, one of the fastest-growing counties in the nation, a corridor of commercial and residential development started in 2003 and is expected to open in 2006. And the widening of Ga. 20 for about 10 miles between I-75 in McDonough and U.S. 19/41 in Hampton is expected to relieve major congestion twice annually when more than 100,000 fans show up to watch NASCAR events at Atlanta Motor Speedway near the intersection of Ga. 20 and U.S.19/41.

The advent of these projects is not surprising, given the growth of the two counties. From 1990 to 2000, census figures show that Henry's population more than doubled, from 58,000 to 119,000, with blacks and other minorities representing 19 percent of the population. During the same time, Clayton's population grew 30 percent to 236,000; demographics shifted from 73 percent white to 52 percent black and about 10 percent Asian and Hispanic.

Despite the population growth and the development it has brought, there's still plenty of history to recall and heritage to preserve. Jonesboro, for example, the county seat of Clayton, was the site of a major Civil War engagement during the Battle of Atlanta. Although growth pushed the courts to a new courthouse on U.S. 19/41, the old Clayton Courthouse in Jonesboro has been restored to its original 1898 facade.

And Henry's county seat, McDonough, maintains its 19th century flavor around its square. While engaged in a downtown revitalization effort, McDonough boosters are pegging the renewal to the town's history, and a welcome center is scheduled to open this year on the square.