1 8 4 6 . Success or ▁appointed ▁December ▁ 4 , ▁ 1 8 4 6 , ▁and ▁subsequently ▁elected ▁to ▁finish ▁the ▁term . ▁| ▁ ▁| ▁Andrew ▁Butler ▁( D ) ▁| ▁Se ated ▁December ▁ 4 , ▁ 1 8 4 6 ▁ ▁| - ▁| ▁Iowa ( 2 ) ▁| ▁col span = 2 ▁| ▁Iowa ▁admitted ▁to ▁the ▁Union ▁December ▁ 2 8 , ▁ 1 8 4 6 ▁| ▁V ac ant ▁| ▁Not ▁filled ▁this ▁term ▁ ▁| - ▁| ▁Iowa ( 3 ) ▁| ▁col span = 2 ▁| ▁Iowa ▁admitted ▁to ▁the ▁Union ▁December ▁ 2 8 , ▁ 1 8 4 6 ▁| ▁V ac ant ▁| ▁Not ▁filled ▁this ▁term ▁ ▁| - ▁| ▁Louisiana ( 2 ) ▁| ▁ ▁| ▁Alexander ▁Bar row ▁( W ) ▁| ▁D ied ▁December ▁ 2 9 , ▁ 1 8 4 6 ▁| ▁ ▁| ▁Pierre ▁Soul é ▁( D ) ▁| ▁Elect ed ▁January ▁ 2 1 , ▁ 1 8 4 7 ▁ ▁| - ▁| ▁Virginia ( 1 ) ▁| ▁ ▁| ▁Isaac ▁S . ▁Pen ny back er ▁( D ) ▁| ▁D ied ▁January ▁ 1 2 , ▁ 1 8 4 7 ▁| ▁ ▁| ▁James ▁M . ▁Mason ▁( D ) ▁| ▁Elect ed ▁January ▁ 2 1 , ▁ 1 8 4 7 ▁| } ▁ ▁House ▁of ▁Representatives ▁ ▁rep lac ements : ▁ 1 2 ▁ ▁Democr ats ▁( D ): ▁ 1