Rev William Walter Overholt was born on 10 May 1892 ^[1] in Iowa, USA, and graduated from the agriculture faculty of Iowa State University. His wife, Mrs Olive Overholt, graduated from the liberal arts faculty of Iowa State University. Later, they went to Northwestern University and Garret Evangelical Theological Seminary to equip themselves. In 1924, they were sent to teach science at the Anglo-Chinese School in Foochow, China.

On completion of the first stage of five years of work, Rev Overholt was posted to Yan Pin (now Nan Pin town, situated upstream of Minjiang River) where he engaged in rural ministry. Upon finishing the second term of work, he returned to Foochow in 1935 and taught at Fukien Christian University where he helped to set up the agriculture college.

In 1937, Rev Overholt went back to America for debriefing. The Japanese invasion of China forced him to stay back in America. He worked for four years doing administrative work in federal agricultural safety and also community service. Later, the couple returned to China and he taught at the Agriculture College of Christian University while his wife served in the Western languages department. When the communists took over in 1949, they stayed in Foochow for 16 months until they were forced to return to America with other missionaries. After taking a year off, they were posted to Sibu, Sarawak, in 1952.

On July 8, 1952, Rev and Mrs Overholt arrived in Sibu as agriculture missionaries. He served in the Bukit Lan farm while Mrs Overholt taught at Methodist Secondary School, Sibu. The Bukit Lan farm, which covered 384 acres, was set aside in 1910 by the second Rajah of Sarawak for the church to use as an experimental farm. In 1912, the church sent Rev Charles E. Davis as an agriculture missionary to set up an agriculture school. James Hoover had also planted Jelutong trees on the farm.

In 1916, Rev Davis returned to America. Ling Kai Cheng was appointed to manage the Bukit Lan property during the first district conference held in June 1946 after World War II. Rev Overholt was the second full-time missionary appointed to take charge of the farm, around the year 1953. The other American  missionary, Rev Thomas Harris, was assigned to the farm of the Iban church in Nanga Mujong. From December 1953 onwards, the farm developed under the management of Rev and Mrs Overholt, and youths deprived of education were given training in agriculture skills.

Before Rev Overholt's arrival, the farm, which was on higher ground, was planted with rubber trees and that was the main source of income for the church. During the Japanese occupation, the farm became the place of refuge for the Chinese from Sibu town. Soon, the Annual Conference started a rural area working committee and planned to set up vocational schools in Sg Teku and Bukit Lan to provide agriculture training for students who had completed primary education, yet had not been offered places in secondary schools. However, the schools closed five months after opening because of the lack of students. Rev Overholt then bought 200 copies of books on agriculture to be distributed in different churches.

He also imported leguminous plants from Indonesia and other places. In 1954, he imported cross-breed goats for breeding. The farm also began to plant sweet potatoes, yam, ginger, corn and other crops. When Tom Harris was on leave, he assisted at Nanga Mujong Agriculture Centre for 14 months.

In 1957, Rev Overholt returned to the US for debriefing. When he returned to Sibu the following year, he was accompanied by Leighton Wiant who was assigned by the mission board to be his successor. On August 11, 1959, seven years after Rev Overholt came to Bukit Lan, he and Mrs Overholt moved into the new parsonage overlooking the Rejang River. He retired on September 23, 1961 and as his boat passed by Bukit Lan, friends stood by the river bank to wave goodbye.

Leighton Wiant introduced wet paddy planting, opened a plant nursery and set up an agriculture school. He also built a health clinic named The Medical Evangelistic Centre, Bukit Lan to serve the local community. The clinic stopped operating in the 1980s.

On September 10, 1997, part of the Bukit Lan Farm was developed into the Bukit Lan Outdoor Retreat Centre.