Google News has many Ontario Historical Newspapers Online and available for free Ontario, Canada research.

Online collections include:

Acton

• Acton Free Press 1894-1895

 Ancaster

• Gore Gazette 1827-1829

Bowmanville

• Canadian Statesman 1877-1878, 1891-1893

Brockville

• Brockville Recorder 1839-1846

Bytown

• Bytown Gazette 1836-1845

Caledonia

• Grand River Sachem 1866-1868

Carp

• Carp Review 1905-1930

Chatham

• Chatham Gleaner 1844-1847

Cobalt

• Cobalt Daily Nugget 1911, 1967, 2001

Fort Frances

• Fort Frances Times 1911-1919

Hamilton

• Daily Spectator 1858

• Hamilton Evening Times 1864-1868

• Hamilton Gazette 1852-1856

• Weekly Times 1858-1864

Kingston

• Canadian Register 1942-1948

• Catholic 1830-1831

• Chronicle & Gazette 1833-1845

• Daily British Whit 1849

• Daily News 1862-1864

• Kingston Chronicle 1820, 1930-1932

• Patriot and Farmer’s Monitor 1832-1834

London

• Catholic Record 1881-1910

• London: Daily Advertiser 1874, 1880-1885

• London Advertiser 1885

• London Evening Advertiser 1864-1865

 Mattawa

• La Sentinelle 1895

 Niagara

• Mail 1851, 1853-1862, 1864-1865, 1867, 1874, 1877-1878

• Niagara Chronicle 1839, 1841, 1845-1851

• Niagara Gleaner 1832-1833, 1835-1836

• Niagara Mail 1847-1848

Ottawa

• Canadian Jewish Chronicle Review 1966-1969

• Daily Citizen 1892-1891

• Ensign 1948-1956

• L’Echo d’Ottawa 1896

• L’Ontario Francais 1902-1903

• La Gazette d’Ottawa 1878-1879

• La Justice 1910-1914

• La Vallee d’Ottawa 1883-1888, 1890

• Le Courrier d’Ottawa 1861-1864, 1870-1871

• Le Courrier Federal 1887-1888, 1917-1925

• Le Federal 1878

• Le Temps 1897, 1901-1916

• Ottawa Citizen 1853-1856, 1859-1871, 1879, 1892-1893, 1895-1987

• Ottawa Daily Citizen 1879-1890

• Ottawa Free Press 1872, 1874-1875, 1877, 1883-1884

• Ottawa Times 1865-1868

• Saturday Citizen 1968-1970, 1972-1976

• Union 1859-1860

• Union 1859-1860, 1865-1866

• United Canada 1888-1896, 1899-1902

Sandwich

• Voice of the Fugitive 1851-1852 (first Black newspaper in Canada, Abolitionist)

• Western Herald 1948-1842

Sarnia

• Sarnia Observer 1857-1860, 1863-1872, 1879-1880, 1882-1895, 1897-1898, 1900

Seaforth

• Huron Expositor 1870, 1876-1878, 1885-1886, 1890-1892

Simcoe

• Norfolk Observer 1840-1842

• Norfolk Reformer 1860-1893

Smith Falls

• Record News 1923, 1974, 1978

• Rideau Record 1894-1895, 1913

St. Catharines

• Farmer’s Journal 1826-1827

• St. Catharines Constitutional 1852, 1854-1856, 1860, 1862-1871

St. David’s

• Spectator 1816-1820

St. Thomas

• Weekly Dispatch 1855-1863

Toronto

• Canadian Jewish Chronicle Review 1966-1969

• Chronicle Review 1969-1970

• Correspondent and Advocate 1834-1837

• Daily Hebrew Journal 1949, 1954, 1960-1962

• Daily Mail and Empire 1895-1900

• Dominion Illustrated 1890-1891 (Montreal & Toronto)

• Examiner 1846-1847

• Globe 1858, 1865, 1869

• Irish Canadian 1863-1892

• Mackenzie’s Weekly Message 1852-1853

• Nation 1874-1876

• North American 1850-1854

• Patriot 1834-1837, 1877-1881

• Toronto Daily Mail 1881-1885, 1887-1895

• Toronto Daily Star 1945

• Toronto Sunday World 1910-1915

• Toronto World 1885-1886, 1890, 1911-1921

• Vochenblatt 1953-1960, 1962-1963 (Canadian Jewish newspaper)

Windsor

• Border Cities Star 1918-1952

• Evening Record 1893-1917

• Saturday Windsor Star 1981-1986

• Windsor Daily Star 1935-1959

• Windsor Herald 1856

• Windsor Record 1917-1918

• Windsor Star 1959-1986

Woodstock

• Oxford Review 2002

York

• Canadian Correspondent 1833-1834

• Canadian Freeman 1825-1873

• Colonial Advocate 1821-1834