The papers of William Mahone span the period 1853 to 1895, with the bulk of the material dating from 1876 to 1892. The collection consists of copies of letters written by Mahone to others, incoming letters to Mahone, subject files on a variety of topics, clippings, and scrapbooks, but primarily focuses on Mahone's railroad and political interests. There is a great deal of overlap of topics between the different series in the collection; thus information concerning Mahone's political and railroad interests is repeated in the different series.

Mahone's involvement in the railroad business dates from 1850 when he became the Assistant Engineer of the Orange and Alexandria Railroad. While there is information about several of the railroads in which Mahone held positions, including both the Orange and Alexandria and the Norfolk and Petersburg Railroads, the bulk of the material concerning railroads is related to the Atlantic, Mississippi, and Ohio Railroad (AMandO). There are both financial and legal papers concerning the AMandO after it ran into financial difficulties in 1873 following the economic panic of that year. Included is correspondence with two Englishmen, John Collinson, who helped Mahone finance a loan to buy the AMandO in 1870, and W. H. Chase, who tried to assist Mahone in saving the railroad. Controversies surrounding the consolidation of railroads in the United States and more particularly in Virginia during the mid to late 19th century are also well documented in the collection.

The bulk of the collection deals with Mahone's political interests and activities. The collection traces the rise of the Readjuster movement in Virginia in the late 1870s, due largely to the efforts of Mahone; Mahone's allegiance to the Republican Party once he was elected to the Senate in 1880; his efforts to build a well organized political machine in Virginia; and finally the loss of support both for Mahone and for the Republican Party in Virginia in the late 1880s.

A central issue in the Readjuster movement was the state's debt, which kept taxes at a high level and almost destroyed the new public school system. The readjusters insisted that the changed conditions of the post-bellum period necessitated the readjustment of the debt. Raising the spectre of class antagonism, Mahone was able to appeal to both poor whites and blacks in order to unite them in a movement of self-interest and reform. This led to the organization of the state-wide Readjuster Party in 1878.

The Readjuster Party won control of the Virginia legislature in 1879 and gained the governorship in 1881 with the election of William E. Cameron. The new party scaled down the debt in the Riddleberger Bill of 1882, enacted laws in social and economic arenas that were of interest to the masses, and, led by Mahone, apportioned governmental offices among the party's leaders. However, in 1883 and thereafter the Readjusters were unable to capture the state legislature or governorship again, although sometimes they lost only narrowly.

Clearly shown through the collection is Mahone's emphasis on organizing the cause of the Readjusters. The focus on organization, including the canvassing of voters before elections, is evident in Mahone's campaigns for the Senate in 1880 and 1886 and for governor of Virginia in 1889. Many of the papers deal with appointing canvassers, creating clubs that would encourage participation in the political process, targeting particular groups to be canvassed such as blacks and "mild" Democrats, making sure political speeches were made in the various precincts, and finding out who had not paid their head-tax and then arranging to have the tax paid. One key element was the Richmond Whig in which Mahone had a financial and editorial interest and which became the official organ of the Readjuster movement.

After Mahone was elected to the United States Senate, he had to choose whether his allegiance would be to the Democrats or Republicans. Once he had aligned himself with the Republicans, Virginia was sometimes viewed as having broken the Solid South, that is, Virginia was seen as one state in the South where Republicans could be elected. Both Virginia and Mahone served as role models for politicians in other southern states who wanted to foster the growth of the Republican Party.

While the collection primarily relates to local and state political matters in Virginia, there are scattered letters in the collection from other areas of the country where the Republican Party was being promoted. There are several letters from William M. Burwell from New Orleans, 1880 to 1884, asking for guidance and giving progress reports on the status of the Republican Party in Louisiana. A letter (1883, March 15) from James T. Beach, Secretary of the Missouri State Republican Committee, relates to his efforts to create a National Cooperative Organization. One of its goals was to secure equal civil and political rights for a free vote.

Mahone was appointed Chair of the United States Senate Committee on Agriculture in 1882 and served on the Committee on Naval Affairs, the Committee on Post-offices and Post-roads, and the Committee on Education and Labor. Evidence of his work on these committees is best shown in the Letterbooks, Correspondence, and Subject Files. It is in the appointment of persons to positions, however, where Mahone's influence is most clearly documented. Requests for patronage positions, particularly in the Post Office, dominate the constituent correspondence. Other letters requested that particular post offices be closed or opened.

Other departments to which persons sought appointment included the Government Printing Office, the Norfolk Navy Yard, the Navy Department, the Treasury Department, and the Internal Revenue Service. Included in both the Correspondence and the Subject Files (Politics: Appointments) series are recommendations, requests and petitions for persons seeking positions.

One incident documented in the collection is a riot that occurred in Danville, Va., on November 3, 1883, three days before the Virginia state elections. Under the Readjuster legislature, blacks held a number of governmental offices in Danville. The Democrats opposed the appointment of blacks and dubbed it "Mahoneism." It is difficult today to pinpoint the origin of the violence that occurred or trace its progress, but as a result of it, several blacks and whites died. Readjusters contended the uprising had been provoked by Democrats for campaign purposes. They also blamed their loss of a majority in the state legislature on the Danville Riot. The collection includes eyewitness accounts of the incident which are located in the Subject Files.

The collection also includes much information about voters and voting patterns down to the precinct level in Virginia during the 1880s. The files relating to election frauds, which date from 1882 to 1889, provide yet another perspective on voting concerns. These files contain standardized forms and letters reporting voting irregularities. The majority of the documented frauds are from 1889 when Mahone lost his bid for governor. There were some who believed that had voting irregularities not occurred, Mahone would have been elected governor in 1889.

The collection records the rise and fall of Mahone's political career in the 1880s, as well as developments and controversies within the Republican Party in Virginia during this period. In 1888 the Republican Party split into factions which led to rival state conventions and delegations to the national convention. The Mahone defeat of 1889 brought a check to Republican activity in Virginia and in 1893 the Republicans made no effort even to nominate candidates for the governorship or the legislature.

Political allies Mahone cultivated in Virginia are among the chief correspondents. They include Frank S. Blair, Stith Bolling, William E. Cameron, Abram Fulkerson, William Lamb, John E. Massey, John Paul, Harrison Holt Riddleberger, and John S. Wise.

There is very little personal material relating to Mahone or his family. There are a few letters from his son William Mahone, Jr., and in the Subject Files there are several folders of financial receipts representing items bought for the Mahone family.

A Duke University doctoral dissertation was written about Mahone in 1932 by Nelson Morehouse Blake entitled William Mahone of Virginia: Builder, Soldier and Insurgent. It was published in 1935 with the title William Mahone of Virginia, Soldier and Political Insurgent. There are additional Mahone papers in the Mahone-McGill Collection in the Rubenstein Library at the University of Virginia Library in Charlottesville, Virginia.