<Table> <Tr> <Th> Date </Th> <Th> Event </Th> <Th> Change Map </Th> </Tr> <Tr> <Th> December 29 , 1845 </Th> <Td> The Republic of Texas was annexed and admitted as the twenty - eighth state , Texas . Texas brought with it a substantial territorial dispute with Mexico . While many sources state that Mexico recognized the independence of the eastern portion of Texas , the treaties were rejected by the Mexican government . Texas formally handed over sovereignty to the United States in a ceremony on February 19 , 1846 . The annexation led to the beginning of the Mexican -- American War a few months later . </Td> <Td> Disputes : </Td> </Tr> <Tr> <Th> June 15 , 1846 </Th> <Td> The Oregon Treaty established the 49th parallel north west of the Lake of the Woods as the continental border ( so it did not include Vancouver Island ) with land held by the United Kingdom . The sharing of Oregon Country ended , and the United States portion became unorganized territory . <P> The treaty was vague on which strait should be the border between Vancouver Island and the continent , thus causing a dispute over ownership of the San Juan Islands . It specified `` through the middle of the said channel and of Fuca Straits , to the Pacific Ocean '' . </P> </Td> <Td> Northwestern North America : Disputes : </Td> </Tr> <Tr> <Th> September 22 , 1846 </Th> <Td> Following the capture on August 18 , 1846 , of Santa Fe , the capital of the Mexican territory of Santa Fe de Nuevo México , a code of laws known as the Kearny Code was created for the area . The region overlapped with Texas ' claim , though Texas had little to no control over the area outside of its eastern quarter . </Td> <Td> Unofficial change : </Td> </Tr> <Tr> <Th> December 28 , 1846 </Th> <Td> The southern portion of Iowa Territory , south of parallel 43 ° 30 ′ north and east of the Big Sioux River , was admitted as the twenty - ninth state , Iowa . The remainder became unorganized territory . </Td> <Td> </Td> </Tr> <Tr> <Th> March 13 , 1847 </Th> <Td> The District of Columbia retroceded Alexandria County back to Virginia . Congress passed the act on July 9 , 1846 , residents of Alexandria County were proclaimed by the president to have agreed to it on September 7 , 1846 , and Virginia took possession of the land on this date . </Td> <Td> </Td> </Tr> <Tr> <Th> May 29 , 1848 </Th> <Td> The southern bulk of Wisconsin Territory , mainly east of the St. Croix River , was admitted as the thirtieth state , Wisconsin . The remainder became unorganized territory . However , the citizens of the remainder decided to continue on with a civil government , and even elected a delegate to the United States House of Representatives who would be seated on January 15 , 1849 , essentially making this region a de facto continuation of Wisconsin Territory . </Td> <Td> </Td> </Tr> <Tr> <Th> July 4 , 1848 </Th> <Td> The Treaty of Guadalupe Hidalgo ended the Mexican -- American War and ceded a large parcel of land from Mexico , consisting of its territories of Alta California and Santa Fe de Nuevo México , and its claim to Texas . Due to a disagreement over the southern border of Santa Fe de Nuevo México , a border dispute began . </Td> <Td> Disputes : </Td> </Tr> <Tr> <Th> August 14 , 1848 </Th> <Td> Oregon Territory was organized from the unorganized territory that was formerly part of Oregon Country . </Td> <Td> </Td> </Tr> <Tr> <Th> February 13 , 1849 </Th> <Td> The boundary dispute between Iowa and Missouri known as the Honey War was resolved by the Supreme Court of the United States . The resulting border was the Sullivan Line that existed before the dispute , roughly splitting the two claims . </Td> <Td> </Td> </Tr> <Tr> <Th> March 3 , 1849 </Th> <Td> Minnesota Territory was organized from unorganized territory east of the Missouri River and the region that had been operating as de facto Wisconsin Territory . </Td> <Td> </Td> </Tr> <Tr> <Th> March 12 , 1849 </Th> <Td> A local government formed the State of Deseret and claimed a vast portion of the southwest , including most of the Mexican Cession . Though it petitioned to be admitted to the United States , the proposal was rejected and , in 1850 , Utah Territory was formed instead . The claimed area overlapped slightly with Texas ' claimed area , as well as part of Oregon Territory . </Td> <Td> Unofficial
<Table> <Tr> <Th> Date </Th> <Th> Event </Th> <Th> Change Map </Th> </Tr> <Tr> <Th> December 29 , 1845 </Th> <Td> The Republic of Texas was annexed and admitted as the twenty - eighth state , Texas . Texas brought with it a substantial territorial dispute with Mexico . While many sources state that Mexico recognized the independence of the eastern portion of Texas , the treaties were rejected by the Mexican government . Texas formally handed over sovereignty to the United States in a ceremony on February 19 , 1846 . The annexation led to the beginning of the Mexican -- American War a few months later . </Td> <Td> Disputes : </Td> </Tr> <Tr> <Th> June 15 , 1846 </Th> <Td> The Oregon Treaty established the 49th parallel north west of the Lake of the Woods as the continental border ( so it did not include Vancouver Island ) with land held by the United Kingdom . The sharing of Oregon Country ended , and the United States portion became unorganized territory . <P> The treaty was vague on which strait should be the border between Vancouver Island and the continent , thus causing a dispute over ownership of the San Juan Islands . It specified `` through the middle of the said channel and of Fuca Straits , to the Pacific Ocean '' . </P> </Td> <Td> Northwestern North America : Disputes : </Td> </Tr> <Tr> <Th> September 22 , 1846 </Th> <Td> Following the capture on August 18 , 1846 , of Santa Fe , the capital of the Mexican territory of Santa Fe de Nuevo México , a code of laws known as the Kearny Code was created for the area . The region overlapped with Texas ' claim , though Texas had little to no control over the area outside of its eastern quarter . </Td> <Td> Unofficial change : </Td> </Tr> <Tr> <Th> December 28 , 1846 </Th> <Td> The southern portion of Iowa Territory , south of parallel 43 ° 30 ′ north and east of the Big Sioux River , was admitted as the twenty - ninth state , Iowa . The remainder became unorganized territory . </Td> <Td> </Td> </Tr> <Tr> <Th> March 13 , 1847 </Th> <Td> The District of Columbia retroceded Alexandria County back to Virginia . Congress passed the act on July 9 , 1846 , residents of Alexandria County were proclaimed by the president to have agreed to it on September 7 , 1846 , and Virginia took possession of the land on this date . </Td> <Td> </Td> </Tr> <Tr> <Th> May 29 , 1848 </Th> <Td> The southern bulk of Wisconsin Territory , mainly east of the St. Croix River , was admitted as the thirtieth state , Wisconsin . The remainder became unorganized territory . However , the citizens of the remainder decided to continue on with a civil government , and even elected a delegate to the United States House of Representatives who would be seated on January 15 , 1849 , essentially making this region a de facto continuation of Wisconsin Territory . </Td> <Td> </Td> </Tr> <Tr> <Th> July 4 , 1848 </Th> <Td> The Treaty of Guadalupe Hidalgo ended the Mexican -- American War and ceded a large parcel of land from Mexico , consisting of its territories of Alta California and Santa Fe de Nuevo México , and its claim to Texas . Due to a disagreement over the southern border of Santa Fe de Nuevo México , a border dispute began . </Td> <Td> Disputes : </Td> </Tr> <Tr> <Th> August 14 , 1848 </Th> <Td> Oregon Territory was organized from the unorganized territory that was formerly part of Oregon Country . </Td> <Td> </Td> </Tr> <Tr> <Th> February 13 , 1849 </Th> <Td> The boundary dispute between Iowa and Missouri known as the Honey War was resolved by the Supreme Court of the United States . The resulting border was the Sullivan Line that existed before the dispute , roughly splitting the two claims . </Td> <Td> </Td> </Tr> <Tr> <Th> March 3 , 1849 </Th> <Td> Minnesota Territory was organized from unorganized territory east of the Missouri River and the region that had been operating as de facto Wisconsin Territory . </Td> <Td> </Td> </Tr> <Tr> <Th> March 12 , 1849 </Th> <Td> A local government formed the State of Deseret and claimed a vast portion of the southwest , including most of the Mexican Cession . Though it petitioned to be admitted to the United States , the proposal was rejected and , in 1850 , Utah Territory was formed instead . The claimed area overlapped slightly with Texas ' claimed area , as well as part of Oregon Territory . </Td> <Td> Unofficial
when did the united states first claim new mexico
when did the united states first claim new mexico
1846
1846