David Richie, 70, the National Park Service official whose often-contentious negotiations with private landowners helped secure the path of the 2,100-mile Appalachian Trail, died of colon cancer Dec. 20 at his home in Hampstead, N.C.

In the early 1970s, Mr. Richie was superintendent of the George Washington Memorial Parkway, where he helped complete a popular bike trail along the Potomac River. His career after that was devoted largely to acquiring land along the 14-state route of the Appalachian Trail.

Running between Georgia and Maine, the pathway had been started in the 1920s, and for many years was run by private groups. It was originally blazed through woods and farmlands where occasional hikers were tolerated. But as the mountain property was acquired by vacationers, no-trespassing signs began to proliferate.

Congress had designated it the first National Scenic Trail in 1968, when about 40 percent of the pathway went through private land. About 200 miles, including 41 in Maryland and Virginia, were not actually in woods but had been shifted to public roads.

Congress established the trail as a national park in 1978 and authorized spending up to $90 million to acquire a permanent corridor 1,000 feet wide and thus protect it from development. The Park Service was given the authority to take land by eminent domain.

Landowners for the most part were reluctant to sell, arguing that the trail was "used only by elitist urbanites and suburbanites" who would contribute nothing to the local economy, recalled Larry Van Meter, former head of the Appalachian Trail Conference. That nonprofit organization has overall responsibility for the trail.

Mr. Richie, as trail project director, undertook the complicated negotiations with owners, including major ski resorts, timber companies and retirees planning to live along the ridge line, Van Meter said.

He said that, rather than dragging much of the acquisition process through the courts, Mr. Richie overcame the many obstacles of a "fundamentally adversarial process" involving thousands of landowners in hundreds of jurisdictions. The acquisition program was not without its bitter disputes.

By 1985, 55,669 acres were acquired through purchase and easement along 372 miles of trail, and the Park Service had gone to court to seize 2,687 acres along 17 miles. Today, more than 99 percent of the trail is protected because of Mr. Richie's efforts, Van Meter said.

Mr. Richie was a native of Moorestown, N.J., and a graduate of Haverford College and George Washington University law school. He served in the Navy and Marine Corps.

He began his Park Service career in the information office of the Bureau of Land Management, where he helped produce a quarterly magazine. He was named assistant superintendent of Mount Rainier National Park and then was superintendent at the park at Grand Coulee Dam. He taught history for two years at his old high school in New Jersey and then became superintendent of the George Washington Parkway.

He completed work begun in the early 1970s by volunteers to establish the Mount Vernon trail, which runs for more than 18 miles along the Potomac River between Roosevelt Island and Mount Vernon. It was the first of the major bike trails in the Washington area.

Mr. Richie was named deputy regional director of the Park Service's northeast regional office in 1974. He retired in 1987, the year after he finished walking the length of the Appalachian Trail. He did work for the Appalachian Trail Conference after leaving government.

He was a member of the board of the American Hiking Society and ran in two Boston Marathons. He moved to North Carolina in 1993.

Survivors include his wife of 47 years, Catherine Campbell Richie of Hampstead; three children, Robert Richie of Takoma Park, David Richie of Fort Collins, Colo., and Deborah Richie Oberbillig of Missoula, Mont.; a brother; a sister; and five grandchildren.