Nestled in the Rock River Valley, just 3 miles south of the town of Oregon, lies a 2,291-acre wooded area that is one of Ogle County's most beautiful and historic sites. Its scenic qualities come from 120-foot bluffs along 3.5 miles of riverfront forested with hardwood and pine trees. The history stems from the individual who, in the early part of the 20th century, augmented the natural hardwood forest by planting pines - Frank O. Lowden (1961-1943) Illinois' governor from 1917-1921. he ardently embraced proper land use and strongly believed in reforestation as a way to retard soil erosion. Over several decades, an estimated 500,000 trees were seeded directly by him or under his supervision.

Since 1992, the tract has been known as Lowden-Miller State Forest. But prior to that Gov. Lowden and his wife, Florence Pullam Lowden, called it Sinnissippi Forest from American Indian terms meaning "rocky river" or "troubled waters." It was part of a large and diverse farming operation that incorporated, not only native hardwoods, but pasture and sandy farmland. Because the soil was of limited use for crops. Lowden experimentally planted white pines and other tree species to see what would grow productively. The earliest plantings of white pines were here before 1910 and are believed to be the oldest in the state.

The governor's love of the land transcended his desire to continue in political office. In his 1916 campaign, Lowden insisted that he wanted to serve only on term as governor as her preferred to return to his farm and forest. In his biography, Squire of the Sinnissippi, Gov. Lowden wrote: "I like to think of this beautiful and fertile spot as the place where my children and my children's children and their children after them will gather long after I have become dust , and in the shade of the old trees my own hand had planted.

The governor remained an avid student of forestry throughout his life. In 1938, he invited the new forestry department at the the University of Illinois to conduct research on the developing forest. Today, with nearly 80 percent of all data on Illinois hardwood forest growth having been developed at Sinnissippi, the forest still serves as a field laboratory for the university.

The family's Sinnissippi Forest Christmas Tree wholesale and retail business began providing high-quality firs and pines for the holiday in 1948, and the operation continues today on land owned and leased by sinnissippi Forest Inc. In 1955, Sinnissippi Forest was designated the first Illinois Tree Farm.

In June 1992, the State of Illinois purchased a 1,186 acre parcel of the forest from a grandson of Gov. and Mrs. Lowden, Warren P. Miller and his wife, Nancy. Warren's brother, Phillip Lowden Miller and his wife, Bonnie, sold and additional 1,039 acres to the state in 1993. In offering their land for sale to the state rather than seeing it subdivided or rezoned for development, the family said they were achieving their goal of keeping the area an actively managed forest and preserving its beauty for future generations.

Named for the family, Lowden-Miller State Forest now totals 2,291 acres. It is located across the Rock River from another DNR property, Castle Rock Sate Park, which oversees its daily operations.

While camping facilities are not available at Lowden-Miller State Forest, other nearby state sites offer them, including Castle Rock State Park or Lowden Memorial State Park, both near Oregon, or White Pines Forest State Park, near Mount Morris.