The bulk of the collection consists of printed copies of speeches that U.S. Senator John H. Mitchell delivered. The topics of these speeches include: tariff bills; Mitchell's opposition to Chinese immigration to the United States; Oregon's electoral vote in the 1876 U.S. presidential election; Mitchell's endorsement of a U.S.-controlled canal being built through Nicaragua; infrastructural improvements to the Columbia River; the 1890s debate over the use of silver for currency; and the Lewis and Clark Centennial Exposition. The collection also includes a speech that Mitchell delivered before becoming a senator, and a speech he gave in response to being indicted for accepting bribes.

There are three items of correspondence in the collection: A May 8, 1890 telegram to James Lotan, regarding a bill for a tariff on wool; a May 8, 1891 letter to Thomas Guinean, which he had sent with a copy of a letter sent to Customs Collector for Alaska E. T. Hatch; and a printed letter to Republican Conference Chair Samuel Hughes, dated February 22, 1897, urging that Oregon Republican legislators appoint a new U.S. senator before the Oregon legislature adjourned.