* 1848 – The United States annexes New Mexico.

* 1848 – California Gold Rush: the New York Herald breaks the news to the East Coast of the United States of the gold rush in California ( although the rush started in January ).

Concerning its domestic borders, the 1803 Louisiana Purchase doubled the nation's geographical area ; Spain ceded the territory of Florida in 1819 ; annexation brought Texas in 1845 ; a war with Mexico in 1848 added California, Arizona and New Mexico.

* 1848 – Women's rights: a two-day Women's Rights Convention opens in Seneca Falls, New York.

He obtained an appointment in 1850 to the United States Military Academy at West Point, New York, from Representative Thomas Hamlet Averett, the man who had defeated his father in the 1848 election.

* 1848 – The ship John Wickliffe arrives at Port Chalmers carrying the first Scottish settlers for Dunedin, New Zealand.

1848 edition of American Phrenological Journal published by Fowlers & Wells, New York City. In the Victorian age, phrenology as a psychology was taken seriously and permeated the literature and novels of the day.

The colony of New Brunswick soon followed on May 1848 when Lieutenant Governor Edmund Walker Head brought in a more balanced representation of Members of the Legislative Assembly to the Executive Council and ceded more powers to that body.

He married his second wife, Sarah Elizabeth Griswold on August 10, 1848 in Utica, New York and had four children ( Samuel b. 1849, Cornelia b. 1851, William b. 1853, Edward b. 1857 ).

While scattered movements and organizations dedicated to women's rights existed previously, the 1848 Seneca Falls Convention in New York is traditionally held as the start of the American women's rights movement.

The Oneida Community, founded by John Humphrey Noyes in Oneida, New York, was a utopian religious commune that lasted from 1848 to 1881.

In 1848, in the New South Wales Legislative Council, William Wentworth proposed a plan to expand the existing Sydney College into a larger university.

* Seneca Falls Convention ( first convention for women's rights ) in Seneca Falls, New York ; 1848

* July 13 – Kate Sheppard, New Zealand Women's suffrage for voting ( b. 1848 )

The California leaves New York Harbor on October 6, 1848, rounds Cape Horn at the tip of South America, and arrives at San Francisco, California after the 4 month 21 day journey.

* High Bridge, part of the former Croton Aqueduct, built in 1848, is the oldest surviving bridge in New York City.

In February 1848 Polk surprised everyone with the Treaty of Guadalupe Hidalgo that ended the Mexican-American War and gave the U. S. vast new territories ( including California, Nevada, Utah, and parts of Wyoming, Colorado, Arizona, and New Mexico ).

As Democrats convened in Baltimore in June 1852, four major candidates vied for the nomination: Lewis Cass of Michigan, the nominee in 1848, who had the backing of northerners in support of the Compromise of 1850 ; James Buchanan of Pennsylvania, popular in the South as well as in his home state ; Stephen A. Douglas of Illinois, candidate of the expansionists and the railroad interests ; and William L. Marcy of New York, whose strength was centered in his home state.

The Oneida Community was a religious commune founded by John Humphrey Noyes in 1848 in Oneida, New York.

* General Zachary Taylor, who became the Whig candidate in 1848 and then President from March 1849 to July 1850, proposed after becoming President that the entire area become two free states, called California and New Mexico but much larger than the eventual ones.

Zachary Taylor avoided the issue as the Whig candidate during the 1848 U. S. presidential election but then as President attempted to sidestep the entire controversy by pushing to admit California and New Mexico as free states immediately, avoiding the entire territorial process and thus the Wilmot Proviso question.

A serious movement for merger of law and equity began in the states in the mid-19th century, when David Dudley Field II convinced New York State to adopt what became known as the Field Code of 1848.

The Seneca Falls Convention was an early and influential women's rights convention held in Seneca Falls, New York, July 19 – 20, 1848.

On April 7, 1848, in response to a citizen's petition, the New York State Assembly passed the Married Woman's Property Act, giving women the right to retain property they brought into a marriage, as well as property they acquired during the marriage.

A group of 44 married women of western New York wrote to the Assembly in March 1848, saying " your Declaration of Independence declares, that governments derive their just powers from the consent of the governed.

On June 2, 1848 in Rochester, New York, Gerrit Smith was nominated as the Liberty Party's presidential candidate.

Lucretia and James Mott visited central and western New York in the summer of 1848 for a number of reasons, including visiting the Cattaraugus Reservation of the Seneca Nation and former slaves living in the province of Ontario, Canada.

" National Reform Nomination For President Gerrit Smith of New York 3 August 1848.

* The Rights of Women, The North Star, Rochester, New York, July 28, 1848

* Bolting Among The Ladies, Oneida Whig, Oneida, New York, August 1, 1848

* Woman's Rights Convention, National Reformer, Auburn, New York, August 3, 1848

* Woman's Rights, The Recorder, Syracuse, New York, August 3, 1848

The Farmington Canal, connecting New Haven with Northampton, Massachusetts, passed through the Farmington River on its eastern bank and was in operation between 1828 and 1848.

The Farmington Canal, which ships traveled from New Haven northward, passed through Hamden between 1825 and 1848 until it was supplanted by railroad travel.

As early as 1848, a separation of Orange and West Haven was considered.

The New York and New Haven Railroad leased the first few sections soon after they opened, obtaining the line to Plainville in 1848 and the extension to Granby plus several branches in 1850.

After attending Yale Law School in 1848, Terry became a lawyer and was appointed clerk of the Superior Court of New Haven County.

Ulysses Grant, aged 26, married Julia Dent, aged 22, on August 22, 1848 at White Haven plantation.

He was a tutor at Yale in 1845 – 1848, assistant professor of Greek in 1848 – 1851, and professor of Greek, succeeding President Woolsey, from 1851 until his death in New Haven, Connecticut.

He moved to New Haven, Connecticut, in 1839 and was instrumental in building the railroad that replaced the canal there in 1848.

Although the New Haven line shares track with the Harlem Line in the Bronx, it only makes one stop along this line at Fordham station due to an 1848 agreement with the Harlem line's predecessor railroad the New York Central.

While the New Haven line's one stop in the Bronx is at Fordham, from 1848 until the 1920s that stop was instead at Woodlawn.

On July 11, 1848, the recently opened New Haven and Northampton Company, running north from New Haven to Plainville, was leased to the NY & NH.

The eastern half of the north shore line, from New Haven east to New London, was chartered in 1848 as the New Haven and New London Railroad, opening in 1852.

White Haven was a plantation worked by slaves at the time Grant was married to his wife in 1848 and remained so until the end of the American Civil War.

The New Haven and New London Railroad was chartered May 1848 to build a line from New Haven, the east end of the New York and New Haven Railroad, east to New London on the Thames River and the south end of the New London, Willimantic and Palmer Railroad.