Bidwell Mansion was the home of General John Bidwell and his wife Annie Ellicott Kennedy Bidwell from the time of their marriage in 1868 until the end of their lives in 1900 and 1918 respectively. Construction of the 26-room mansion began in 1865, prior to John Bidwell's first introduction to his future bride, which occurred late in 1865. The Bidwells were married April 16, 1868 in Washington, D.C. with then President Andrew Johnson and future president Ulysses S. Grant among the guests. During their courtship and prior to their marriage, the Bidwells planned the furnishings of the Mansion as well as the finishing stages of construction. 

Henry W. Cleaveland was the architect of the $56,000 house. The most modern gas lighting, plumbing and water systems were installed, and every detail of hardware and handwork was meticulously finished. The overall style of the three-story brick structure was that of an Italian villa or country estate; an informal, warmly romantic style that was further heightened by covering the brick walls with pink-tinted plaster and painting the wood trim a complimentary brown tone. The outside and inside walls were two thicknesses of brick with an air space in between. On the ground floor is a vary spacious entry hall, a formal parlor, dining room, library and the General's office. The kitchen and laundry room were located in the rear. Surrounded by a balcony over the wide first floor veranda, the second story contains five bedrooms, two bathrooms, servants quarters, and a room equipped by Mrs. Bidwell in which she taught Native American girls to sew. A ballroom and six additional guest rooms are located on the third floor, plus a private office for the General. All of these rooms were filled with furniture of the Victorian era; dark, gleaming wood polished to a high degree, with many tables topped with marble. Off-white lace curtains and wall to wall carpeting, together with marbleized slate fireplaces, completed the décor. 

The Bidwell's were firm advocates of western hospitality and the Mansion was used extensively for the entertainment of friends and special guests. Some of their guests included President and Mrs. Rutherford B. Hayes, General William T. Sherman, Susan B. Anthony, Frances Willard, Govenor Leland Standford, John Muir, Asa Gray and Sir Joseph Hooker.