December 2, 1845: President Polk announced to Congress that the Monroe Doctrine should be strictly enforced and that the United States should aggressively expand into the West.
April 25, 1846: Open conflict over border disputes of Texas's boundaries began the Mexican–American War
This list is arranged by chamber, then by state. Senators are listed by class and representatives are listed by district.
Skip to House of Representatives, below
Senate
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 with this Congress, facing re-election in 1850; Class 2 meant their term ended with this Congress, facing re-election in 1846; and Class 3 meant their term began in the last Congress, facing re-election in 1848.
House of Representatives
The names of members of the House of Representatives are preceded by their district numbers.
Changes in membership
The count below reflects changes from the beginning of the first session of this Congress.
