Catherine Buchanan Alderton (1869 – 9 November 1951[1]), was a British Liberal Party politician and suffragist.

Catherine Alderton was the daughter of the Reverend Thomas Robinson, minister of Lion Walk Congregational Church from 1886 to 1902.

She opposed the decision of the NUWSS to extend their Elections Fighting Fund policy of campaigning against Liberal by-election candidates who supported votes for women.

In October 1922, very much at the last minute, Alderton was adopted by Edinburgh South Liberal Association as their prospective parliamentary candidate.

In another straight fight with a Unionist she encountered a swing against her and was out-polled by 2 to 1; In 1923 she became Vice-Chairman of the Women's Liberal Federation.

[18] The general election soon followed at which she came third, only managing to retain the Liberal vote from 1924; However, it was felt that Alderton had done remarkably well at such short notice.

In Colchester as in many other places, the Liberals decided not to oppose the sitting Conservative Oswald Lewis and Alderton went to the extent of publicly supporting him against his Labour challenger.

[22] Although she did not stand for parliament again she remained committed to supporting the Liberal Party, even after it left the National Government in 1933.

In 1928 she shifted her interest in local government from Colchester to the Essex County Council being the first woman to be elected to that body.

[30] Her services to local government in Essex were recognised in January 1944 in the King's New Year Honours List, when she was awarded the MBE.