- British Attitude toward the Oregon Question, 1815–1846, 1911
- Jesse Applegate: Pioneer and State Builder, 1912
- Francis Parkman, 1923
- Prince Lucien Campbell, 1926
He edited two important overland journals:
- Across the Plains in 1850, by John Steele, 1930
- Day with the Cow Column in 1843, by Jesse Applegate, 1934
Articles in the Oregon Historical Quarterly:
- "Survey of Public Education in Eugene" (March, 1901)
- "Notes on the Colonization of Oregon" (December, 1905)
- "Documents Relative to Warre and' Vavasour's Military Reconnoissance in Oregon, 1845–46" (March, 1909)
- "Career of Frederic George Young" (March, 1929)
- "Harvey W. Scott, Historian" (September, 1933)
Articles in the Wisconsin Magazine of History:
- "Turner's Frontier Philosophy" (June, 1933)
- "Turner's America" (June, 1934)
- "Turner's Early Writings" (December, 1938)
Biographies written for the Dictionary of American Biography:
George Abernethy; W. L . Adams; Jesse Applegate; G. H. Atkinson; R. P. Boise; Prince L. Campbell; H. W. Corbett; P. J. DeSmet; James R. Doolittle; James D. Doty; Lyman C. Draper; T. J. Farnham; John P. Gaines; Robert Greenhow; LaFayette Grover; Mortimer M. Jackson; Hall J. Kelley; Elisha W. Keyes; Joseph Lane; John McLoughlin; James W. Nesmith; Samuel Parker; Alexander W. Randall; Jeremiah M. Rusk; Jedediah Smith; Isaac Ingalls Stevens; Marcus Whitman; Nathaniel J. Wyeth
Besides numerous articles in the Wisconsin Magazine of History, which he edited, and other articles published in periodicals, he wrote the following seven books on Wisconsin:
- A History of Agriculture in Wisconsin, 1922
- Yankee and Teuton in Wisconsin, 1922–23
- Wisconsin Domesday Book I, 1924
- Four Wisconsin Counties, Prairie and Forest, 1927
- Winnebago-Haricon Basin, 1927
- Rural Life of a Western State, 1930
- The Wisconsin Lead Region, 1931
- Memoirs of Jeremiah Curtin, 1940
Writings on the contributions of German-Americans to our national life, going with characteristic expansiveness from Germans in Wisconsin to Carl Schurz:
- Yankee and Teuton in Wisconsin, 1922–23
- Life of Carl Schurz, 1929
- Intimate Letters of Carl Schurz, 1929
Writings on agriculture, including the earliest and one of the latest of his books, with 34 years between—a paramount interest that never had a productive opportunity but that never died:
- Origin of the System of Land Grants for Education, 1902
- His various books and articles on Wisconsin agriculture
- The Social History of American Agriculture, 1936
