Question: The Downtown Oakland Historic Districit is part of what California County?

Context paragraphs:
Oakland Charter Academy: Oakland Charter Academy (OCA) originally Jingletown Charter School, is a charter school in Oakland, California serving middle school students.  Opened in 1994, it is the first and oldest charter school in Oakland and one of the first in California.  After a dramatic turnaround, it became the second public school in Oakland to win the National Blue Ribbon award.  The school was also designated the Hart Vision Charter School of the Year Award for 2009 by the California Charter Schools Association.  The Amethod Public Schools system grew out of Oakland Charter Academy, and now includes Oakland Charter High School and Downtown Charter Academy located in downtown Oakland.  The system also operates Benito Juarez Elementary School, Richmond Charter Academy and John Henry High School in Richmond.

Oaksterdam, Oakland: Oaksterdam is a cultural district on the north end of downtown Oakland, California, where medical cannabis in a variety of competitively priced smokeable and edible preparations is available for purchase in multiple cafes, clubs, and patient dispensaries.  Oaksterdam is located on the north end of downtown Oakland, between downtown proper, the Lakeside, and the financial district.  It is roughly bordered by 14th Street on the southwest, Harrison Street on the southeast, 19th Street on the northeast, and Telegraph Avenue on the northwest.  The name is a portmanteau of "Oakland" and "Amsterdam," the capital of the Netherlands, where marijuana is semi-legal.  Founded in 2007, and located in the heart of Oakland, Oaksterdam University is the nation's first cannabis college.  The school's mission is to provide quality training for the cannabis industry.  Those interested in learning more about this emerging industry should learn to do so safely and responsibly in accordance with the law.  At Oaksterdam University, state vs. federal law is the first class you are taught, in an effort to help you understand the law before you are taught anything else.  The faculty at Oaksterdam University encompasses some of the most prominent names in the industry.  Many of the faculty members not only helped write state law but also took medical marijuana cases to the Supreme Court.  Oaksterdam University continues to educate, retaining its support from the city of Oakland.

West Oakland, Oakland, California: West Oakland is a neighborhood situated in the northwestern corner of Oakland, California, United States, situated west of Downtown Oakland, south of Emeryville, and north of Alameda.  The neighborhood is located along the waterfront at the Port of Oakland and at the eastern end of the San Francisco–Oakland Bay Bridge.  It lies at an elevation of 13 feet (4 m).

Oakland Public Library: The Oakland Public Library is the public library in Oakland, California.  Opened in 1878, the Oakland Public Library currently serves the city of Oakland, along with neighboring smaller cities Emeryville and Piedmont.  The Oakland Public Library has the largest collection of any public library in the East Bay, featuring approximately 1.5 million items.  It consists of a main library located in downtown Oakland, and 16 branch libraries throughout the city (see below).

Oakland, California: Oakland is the largest city and the county seat of Alameda County, California, United States.  A major West Coast port city, Oakland is the largest city in the East Bay region of the San Francisco Bay Area, the third largest city overall in the San Francisco Bay Area, the eighth largest city in California, and the 45th largest city in the United States, with a population of 419,267 as of 2015 .  It serves as a trade center for the San Francisco Bay Area; its Port of Oakland is the busiest port in the San Francisco Bay, the entirety of Northern California, and the fifth busiest in the United States of America.  The city was incorporated in 1852.

Oakland Wye: The Oakland Wye is an underground junction in downtown Oakland serving the Bay Area Rapid Transit (BART) system, where trains can switch between (a) the northbound Richmond or Pittsburg/Bay Point lines (first station: 12th Street/Oakland City Center, underground), (b) the westbound San Francisco lines (first station: West Oakland, elevated) , and (c) the southbound Fremont or Dublin/Pleasanton lines (first station: Lake Merritt, underground).  The Oakland Wye has been described as one of the central and most complex part of the BART system, and is a speed bottleneck for the whole system because all BART trains pass through it.

Interstate 980: Interstate 980 (I-980) is a short Interstate Highway spur entirely within Oakland, California, connecting Interstate 580 and State Route 24 to Interstate 880 near Downtown Oakland.  I-980 passes the Oakland Convention Center and near the famous Jack London Square.  I-980 is commonly considered the dividing line between Downtown Oakland and West Oakland.  The freeway was planned as the eastern approach to the San Francisco Bay Southern Crossing.  It is officially known as the John B. Williams Freeway, after the former director of the City of Oakland's Office of Community Development.

North Oakland, Oakland, California: North Oakland is a region in Oakland, California, United States, bordered by Downtown Oakland, Oakland Hills, and the adjacent cities of Berkeley, Emeryville and Piedmont.  Annexed to Oakland in 1897.  It is known as the birthplace of the Black Panther Party and is the childhood home of both the co-founders, which are Dr. Huey P. Newton and Bobby Seale.  It is also the birthplace and childhood home of Sue Draheim, internationally recognized fiddler.

Downtown Oakland Historic District: The Downtown Oakland Historic District, in the Downtown Oakland area of Oakland, California, was listed on the National Register of Historic Places in 1998.  The listing included 43 contributing buildings, one contributing site and one contributing object.

16th Street Station: The Oakland 16th Street Station (also known as the Oakland Central Station) was one of three train stations in Oakland, California, United States at the start of the 20th century.  The Beaux-Arts building was designed by architect Jarvis Hunt, a preeminent train station architect, and opened in 1912.  For decades the 16th Street Station was the main Oakland station for Southern Pacific (SP) through trains.  The elevated platforms were used for the East Bay Electric Lines, which went around the East Bay and after 1939 over the Bay Bridge until 1941, when it was sold to the Key System.  It was a companion (or "city station") for Oakland Pier, two miles away, which was demolished in 1960.  After the pier was demolished people switched to buses at this station which took passengers across the Bay Bridge to the SP's Third and Townsend Depot.  Amtrak (the National Railroad Passenger Corporation) used this station as its main Oakland stop for nearly two decades.  It also had buses across the bridge but ran them to the Transbay Terminal instead.  The station was severely damaged in the 1989 Loma Prieta earthquake, but continued serving trains at an adjacent building.  It closed in 1994, having been replaced by the stations in nearby Emeryville and Jack London Square.  The last Amtrak train serviced the station on August 5, 1994, after which passengers accessed downtown Oakland via the Emeryville Station, until Jack London Station opened in May 1995.

Supporting paragraphs: Downtown Oakland Historic District Oakland, California
Answer: Alameda County