Newton LeGayet Mackay (1832 – May 20, 1886) was a Canadian lawyer and political figure. He represented Cape Breton in the House of Commons of Canada from 1872 to 1878 as a Conservative and then Liberal member.^[1]

He was born in Halifax, Nova Scotia,^[1] the son of William McKay, and was educated there. Mackay was called to the Nova Scotia bar in 1859 and named a Queen's Counsel in 1872. He ran unsuccessfully for a seat in the Nova Scotia assembly in 1867 and 1871 before he was elected to the House of Commons. Mackay became a Liberal following the Pacific Scandal.^[2] After his defeat by Hugh McLeod in 1878, he was an unsuccessful candidate in each subsequent federal election until his death in 1886^[1] in Sydney. In 1879, he married Kate Bown. Mackay served as treasurer for Cape Breton County.^[3]

Electoral record

v t e 1882 Canadian federal election: Cape Breton
Party	Candidate	Votes	%	Elected
	Conservative	William McDonald	1,297	–	Y
	Conservative	Murray Dodd	1,237	–	Y
	Liberal–Conservative	William Mackenzie McLeod	1,124
	Liberal	Newton LeGayet Mackay	1,013
	Liberal–Conservative	Hector Francis McDougall	934

v t e 1878 Canadian federal election: Cape Breton
Party	Candidate	Votes	%	Elected
	Liberal–Conservative	Hugh McLeod	2,056	–	Y
	Conservative	William McDonald	2,051	–	Y
	Liberal	Newton LeGayet Mackay	1,153
	Unknown	Walter Young	696

v t e 1874 Canadian federal election: Cape Breton
Party	Candidate	Votes	%	Elected
	Conservative	William McDonald	1,251	–	Y
	Liberal	Newton LeGayet Mackay	1,136	–	Y
	Liberal–Conservative	Hugh McLeod	1,108

v t e 1872 Canadian federal election: Cape Breton
Party	Candidate	Votes	%	Elected
	Conservative	Newton LeGayet MacKay	1,240	–	Y
	Conservative	William McDonald	1,038	–	Y
	Liberal–Conservative	Hugh McLeod	932
	Liberal–Conservative	James McKeagney	882
Source: Canadian Elections Database[4]