The count below identifies party affiliations at the beginning of the first session of this Congress, and includes members from vacancies and newly admitted states, when they were first seated. Changes resulting from subsequent replacements are shown below in the "Changes in membership" section.
Senators were elected by the state legislatures every two years, with one-third beginning new six year terms with each Congress. Preceding the names in the list below are Senate class numbers, which indicate the cycle of their election. In this Congress, Class 1 meant their term began in the last Congress, requiring reelection in 1874; Class 2 meant their term began in this Congress, requiring reelection in 1876; and Class 3 meant their term ended in this Congress, requiring reelection in 1872.
The names of members of the House of Representatives elected statewide on the general ticket or otherwise at-large, are preceded by an "A/L," and the names of those elected from districts, whether plural or single member, are preceded by their district numbers.
Many of the congressional district numbers are linked to articles describing the district itself. Since the boundaries of the districts have changed often and substantially, the linked article may only describe the district as it exists today, and not as it was at the time of this Congress.