Eastern Canada is generally considered to be the region of Canada

Canada

Canada is a North American country consisting of ten provinces and three territories. Located in the northern part of the continent, it extends from the Atlantic Ocean in the east to the Pacific Ocean in the west, and northward into the Arctic Ocean...

 east of Manitoba

Manitoba

Manitoba is a Canadian prairie province with an area of . The province has over 110,000 lakes and has a largely continental climate because of its flat topography. Agriculture, mostly concentrated in the fertile southern and western parts of the province, is vital to the province's economy; other...

, consisting of the following provinces

Provinces and territories of Canada

The provinces and territories of Canada combine to make up the world's second-largest country by area. There are ten provinces and three territories...

:

• New Brunswick
  New Brunswick
  New Brunswick is one of Canada's three Maritime provinces and is the only province in the federation that is constitutionally bilingual . The provincial capital is Fredericton and Saint John is the most populous city. Greater Moncton is the largest Census Metropolitan Area...
  
  
• Newfoundland and Labrador
  Newfoundland and Labrador
  Newfoundland and Labrador is the easternmost province of Canada. Situated in the country's Atlantic region, it incorporates the island of Newfoundland and mainland Labrador with a combined area of . As of April 2011, the province's estimated population is 508,400...
  
  
• Nova Scotia
  Nova Scotia
  Nova Scotia is one of Canada's three Maritime provinces and is the most populous province in Atlantic Canada. The name of the province is Latin for "New Scotland," but "Nova Scotia" is the recognized, English-language name of the province. The provincial capital is Halifax. Nova Scotia is the...
  
  
• Ontario
  Ontario
  Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....
  
  
• Prince Edward Island
  Prince Edward Island
  Prince Edward Island is a Canadian province consisting of an island of the same name, as well as other islands. The maritime province is the smallest in the nation in both land area and population...
  
  
• Quebec
  Quebec
  Quebec or is a province in east-central Canada. It is the only Canadian province with a predominantly French-speaking population and the only one whose sole official language is French at the provincial level....
  
  

Ontario and Quebec comprise Central Canada

Central Canada

Central Canada is a region consisting of Canada's two largest and most populous provinces: Ontario and Quebec. Due to their high populations, Ontario and Quebec have traditionally held a significant amount of political power in Canada, leading to some amount of resentment from other regions of the...

, while the other provinces constitute Atlantic Canada

Atlantic Canada

Atlantic Canada is the region of Canada comprising the four provinces located on the Atlantic coast, excluding Quebec: the three Maritime provinces – New Brunswick, Prince Edward Island, and Nova Scotia – and Newfoundland and Labrador...

. Nova Scotia, New Brunswick, and Prince Edward Island are also known as the Maritime Provinces.
The Canadian Press

Canadian Press

Canadian Press Enterprises Inc. is the entity which "will take over the operations of the Canadian Press" according to a November 26, 2010 article in the Toronto Star...

 defines Eastern Canada as everything east of and including Thunder Bay

Thunder Bay

-In Canada:Thunder Bay is the name of three places in the province of Ontario, Canada along Lake Superior:*Thunder Bay District, Ontario, a district in Northwestern Ontario*Thunder Bay, a city in Thunder Bay District*Thunder Bay, Unorganized, Ontario...

, Ontario

Ontario

Ontario is a province of Canada, located in east-central Canada. It is Canada's most populous province and second largest in total area. It is home to the nation's most populous city, Toronto, and the nation's capital, Ottawa....

.
The total population of this region is about 22,507,099, or about 70% of Canada's population.