Question: Oakland Female Seminary was the first girls' school west of what second-largest drainage system in North America?

Context paragraphs:
First Cherokee Female Seminary Site: The first Cherokee Female Seminary was a boarding school opened by the Cherokee Nation in 1851 in Park Hill, Oklahoma.  On Easter Sunday 1887, a fire burned the building, but the head of the school, Florence Wilson, made sure all the girls got out.  Two years later, in 1889, the new Cherokee Female Seminary reopened and still stands just north of Tahlequah.

Oakland Female Seminary: Oakland Female Seminary (also Oakland Seminary for Young Ladies) was a private girls' school located in the U.S. state of California.  Situated at 528 Eleventh Street in Oakland, it contained 57 rooms.  Founded on November 8, 1858, by Millicent Kittredge Blake, it was the first girls' school established west of the Mississippi River.  Carrie Stevens Walter was the valedictorian of the first graduating class.

Millicent Kittredge Blake: Millicent Kittredge Blake (alternate spelling, Meliscent; née Millicent Kittredge; January 11, 1822 - November 27, 1907) was an Oakland, California pioneer, and an American educator from the U.S. state of New York.  She founded the Oakland Female Seminary (aka Oakland Seminary for Young Ladies; Blake Seminary) on November 8, 1858.  It was the first girls school established to the west of the Mississippi River.

Amos Eaton: Amos Eaton (17 May 1776 – 10 May 1842) was an American botanist, geologist, and educator who is considered the founder of the modern scientific prospectus in education, which was a radical departure from the American liberal arts tradition of classics, religious classes, lecture, and recitation.  Eaton co-founded the Rensselaer School in 1824 with Stephen van Rensselaer III "in the application of science to the common purposes of life".  His books in the eighteenth century were among the first published for which a systematic treatment of the United States was attempted, and in a language that all could read.  His teaching laboratory for botany in the 1820s was the first of its kind in the country.  Eaton's popular lectures and writings inspired numerous thinkers, in particular women, whom he encouraged to attend his public talks on experimental philosophy.  Emma Willard would found the Troy Female Seminary (Emma Willard School), and Mary Mason Lyon, the Mount Holyoke Female Seminary (Mount Holyoke College).  Eaton held the rank of senior professor at Rensselaer until his death in 1842.

Mississippi River: The Mississippi River is the chief river of the second-largest drainage system on the North American continent, second only to the Hudson Bay drainage system.  Flowing entirely in the United States (although its drainage basin reaches into Canada), it rises in northern Minnesota and meanders slowly southwards for 2320 mi to the Mississippi River Delta at the Gulf of Mexico.  With its many tributaries, the Mississippi's watershed drains all or parts of 31 U.S. states and 2 Canadian provinces between the Rocky and Appalachian Mountains.  The Mississippi ranks as the fourth-longest and fifteenth-largest river in the world by discharge.  The river either borders or passes through the states of Minnesota, Wisconsin, Iowa, Illinois, Missouri, Kentucky, Tennessee, Arkansas, Mississippi, and Louisiana.

Cherokee Female Seminary: The Cherokee Female Seminary, (not to be confused with the first Cherokee Female Seminary), serves as the centerpiece of Northeastern State University, located in Tahlequah, Oklahoma, United States.  The building was constructed to replace the original Cherokee Female Seminary that burnt to the ground Easter Sunday 1887.  The Cherokee Council chose to rebuild the school on a 40 acre site north of Tahlequah, near Hendricks Spring.  Two years later, on May 7, 1889, the dedication ceremonies were held in honor of the new building.  The Female Seminary was owned and operated by the Cherokee Nation until March 6, 1909 when the State Legislature of Oklahoma passed an act providing for the creation and location of Northeastern State Normal School at Tahlequah, Oklahoma, and for the purchase form the Cherokee Tribal Government of the building, land, and equipment of the Cherokee Female Seminary.  At the start of the next academic year, on September 14, the first classes were held at the newly created Northeastern State Normal School, now Northeastern State University.

Bethlehem Female Seminary: The Bethlehem Female Seminary was established in 1742 in Germantown, Pennsylvania and was the first Protestant boarding school for girls in what became the United States.  The Bethlehem Female Seminary later became known as the Moravian Female Seminary, and in 1863 the Seminary was established as Moravian College.

Emma Willard: Emma Hart Willard (February 23, 1787 – April 15, 1870) was an American women's rights activist who dedicated her life to education.  She worked in several schools and founded the first school for women's higher education, the Troy Female Seminary in Troy, New York.  With the success of her school, Willard was able to travel across the country and abroad, to promote education for women.  The Troy Female Seminary was renamed the Emma Willard School in 1895 in her honor.

Oak Ridge Seminary: The Oak Ridge Seminary (Oak Ridge Female Seminary, Oak-Ridge Academy) was an antebellum school for "young ladies" west of the borough of Gettysburg, Pennsylvania.  One of 2 girls schools used as an American Civil War hospital for Battle of Gettysburg casualties, the female seminary had also been used as a prison, and General Lee's "Headquarters and tents [were] pitched in the space adjoining Oak Ridge Seminary" (a field was "on the east side of Miss Carrie Sheads' School".)

Steubenville Female Seminary: Steubenville Female Seminary, also known as Beatty's Seminary for Young Ladies or Steubenville Seminary, was a female seminary in Steubenville, Ohio.  It was founded by Presbyterian minister Charles Clinton Beatty in 1829.  Beatty served as Superintendent and his wife, Hetty Elizabeth Beatty, served as principal.  The school had 7 students during the first year.  The campus in Steubenville, Ohio gave a view of the surrounding hills.

Supporting paragraphs: Oakland Female Seminary Mississippi River
Answer: Mississippi River