Lac-Saint-Jean-Est (French pronunciation: [lak sɛ̃ ʒɑ̃ ɛst]) is a regional county municipality in the Saguenay–Lac-Saint-Jean region of Quebec, Canada. The seat is Alma. In 2016, 99.3% reported that they spoke French most often at home, according to the census.

There are 18 subdivisions within the RCM:

Historical Census Data - Lac-Saint-Jean-Est Regional County Municipality, Quebec

Year Pop. ±% 1991 51,963 —     1996 52,401 +0.8% 2001 51,760 −1.2%	Year Pop. ±% 2006 51,170 −1.1% 2011 52,520 +2.6% 2016 52,741 +0.4%

Canada Census Mother Tongue - Lac-Saint-Jean-Est Regional County Municipality, Quebec
Census		Total		French				English				French & English				Other
Year		Responses		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %		Count	Trend	Pop %
2016		52,080		51,520	0.3%	98.92%		180	21.7%	0.44%		95	11.8%	0.18%		285	83.9%	0.55%
2011		51,835		51,365	2.7%	99.09%		230	24.3%	0.44%		85	88.9%	0.16%		155	61.3%	0.30%
2006		50,630		50,000	1.0%	98.76%		185	15.9%	0.37%		45	59.1%	0.08%		400	247.8%	0.79%
2001		50,935		50,490	1.6%	99.13%		220	12.8%	0.43%		110	29.4%	0.22%		115	21.1%	0.23%
1996		51,685		51,310	n/a	99.27%		195	n/a	0.38%		85	n/a	0.16%		95	n/a	0.18%

Highways and numbered routes that run through the municipality, including external routes that start or finish at the county border:

• List of regional county municipalities and equivalent territories in Quebec