Matthew Vassar assumed an interest in the development of the Hudson River Railroad. 

Matthew Vassar visited Saratoga Springs and had a full-length silhouette cut by the prominent French artist, August Edouart. This was later given to the Vassar College library by Helen Evarts '17. 

First telegraph message, "What hath God wrought", was transmitted over a line between Baltimore and Washington. The station was under the direction of Samuel F. B. Morse, later a charter trustee of Vassar. 

Matthew Vassar and his wife, accompanied by his secretary, Cyrus Swan—later a charter trustee—sailed for Europe in the packet-ship Northumberland. "…about 1845 I visited Europe & while in London visited the famous 'Guy' Hospitall, the founder of which a family relative, '[Thomas] Guy'…had the honor of being named after.—Seeing this Institution first suggested the idea of devoting a portion of my Estate to some Charitable purpose, and about this period took quite an interest in a niece of mine, Lydia Booth, who was then engaged in a small way in the tuition of Children resulting in after years in the opening of a female seminary in Poughkeepsie being the first of its kind excepting one other, Mrs. Conger, in the village.”      Elizabeth Hazelton Haight, ed., Autobiography and Letters of Matthew Vassar

The United States declared war on Mexico. 

Having negotiated the route of the Hudson River Railroad from its planned site, about 30 miles east of Poughkeepsie, to the riverfront, Matthew Vassar was elected president of the company. The railroad began operation in 1849.

The Treaty of Guadalupe Hidalgo, approved by the U.S. Senate in March, was ratified by the Mexican Congress, ending the war with Mexico.

As chairman of a committee of the Poughkeepsie village board of trustees, of which he was president, Matthew Vassar purchased the 45-acre “Allen farm” southwest of the village, with the intention of selling it to subscribers for a greatly needed new public cemetery.  Meeting with “unaccountable indifference,” as The Poughkeepsie Eagle put it, he commenced improvements to the site suitable for both a cemetery and a private estate in case the cemetery venture did not succeed.

Andrew Jackson Downing of Newburgh, a prominent architect and the most important American landscape designer, began plans for the land’s development.  When the cemetery committee decided on a larger piece of nearby property on the bank of the Hudson, Downing proceeded to develop plans for a country estate for Vassar to be called Springside.  On July 28, 1852, Downing died, along with 80 others, when a boiler aboard the river steamer Henry Clay exploded into flames which quickly destroyed the wooden craft.

Although Vassar proceeded with several parts of Downing’s extensive plan for Springside, the main house was never built.  Vassar summered in a farmer’s cottage on the property, and after the death of his wife Catherine in 1863 he lived at Springside year-round.