Query: In the early 20th century, state and federal governments began aggressively fighting wildfires and trying to keep them as small as possible.

Relevant passages:
California <=SEP=> California ( -LSB- kælᵻˈfɔːrnjə , _ - ni.ə -RSB- , ) is the most populous state in the United States and the third most extensive by area . Located on the western ( Pacific Ocean ) coast of the U.S. , California is bordered by the other U.S. states of Oregon , Nevada , and Arizona and shares an international border with the Mexican state of Baja California . The state capital is Sacramento . Los Angeles is California 's most populous city , and the country 's second largest after New York City . The Greater Los Angeles Area and the San Francisco Bay Area are the nation 's second - and fifth-most populous urban regions , respectively . California also has the nation 's most populous county , Los Angeles County , and its largest county by area , San Bernardino County .   California 's diverse geography ranges from the Pacific Coast in the west to the Sierra Nevada mountain range in the east ; and from the redwood -- Douglas fir forests in the northwest to the Mojave Desert in the southeast . The Central Valley , a major agricultural area , dominates the state 's center . Though California is well-known for its warm Mediterranean climate , the large size of the state means it can vary from moist temperate rainforest in the north , to arid desert in the interior , as well as snowy alpine in the mountains .   What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries . The Spanish Empire then claimed it as part of Alta California in their New Spain colony . The area became a part of Mexico in 1821 following its successful war for independence , but was ceded to the United States in 1848 after the Mexican -- American War . The western portion of Alta California then was organized as the State of California , and admitted as the 31st state on September 9 , 1850 . The California Gold Rush starting in 1848 led to dramatic social and demographic changes , with large-scale emigration from the east and abroad with an accompanying economic boom .   If it were a country , California would be the 6th largest economy in the world and the 35th most populous . It is also regarded as a global trendsetter in both popular culture and politics , and is the origin of the film industry , the hippie counterculture , the Internet , and the personal computer , among others . Fifty-eight percent of the state 's economy is centered on finance , government , real estate services , technology , and professional , scientific and technical business services . The San Francisco Bay Area has the nation 's highest median household income by metropolitan area , and is the headquarters of three of the world 's largest 40 firms by revenue , Chevron , Apple , and McKesson . Although it accounts for only 1.5 percent of the state 's economy , California 's agriculture industry has the highest output of any U.S. state .

Maryland <=SEP=> Maryland ( -LSB- ˈmɛrᵻlənd -RSB- ) is a state in the Mid-Atlantic region of the United States , bordering Virginia , West Virginia , and Washington , D.C. to its south and west ; Pennsylvania to its north ; and Delaware to its east . The state 's largest city is Baltimore , and its capital is Annapolis . Among its occasional nicknames are Old Line State , the Free State , and the Chesapeake Bay State . The state is named after Henrietta Maria of France , the wife of Charles I of England .   One of the original Thirteen Colonies , Maryland is considered to be the birthplace of religious freedom in America , when it was formed by George Calvert in the early 17th century as an intended refuge for persecuted Catholics from England . George Calvert was the first Lord of Baltimore and the first English proprietor of the then-Maryland colonial grant . Maryland was the seventh state to ratify the United States Constitution , and played a pivotal role in the founding of Washington , D.C. , which was established on land donated by the state .   Maryland is one of the smallest U.S. states in terms of area , as well as one of the most densely populated , with around six million residents . , Maryland had the highest median household income of any state , owing in large part to its close proximity to the nation 's capital and a highly diversified economy spanning manufacturing , services , and biotechnology .

Wisconsin <=SEP=> Wisconsin ( -LSB- wᵻˈskɒnsᵻn -RSB- ) is a U.S. state located in the north-central United States , in the Midwest and Great Lakes regions . It is bordered by Minnesota to the west , Iowa to the southwest , Illinois to the south , Lake Michigan to the east , Michigan to the northeast , and Lake Superior to the north . Wisconsin is the 23rd largest state by total area and the 20th most populous . The state capital is Madison , and its largest city is Milwaukee , which is located on the western shore of Lake Michigan . The state is divided into 72 counties .   Wisconsin 's geography is diverse , with the Northern Highland and Western Upland along with a part of the Central Plain occupying the western part of the state and lowlands stretching to the shore of Lake Michigan . Wisconsin is second to Michigan in the length of its Great Lakes coastline .   Wisconsin is known as `` America 's Dairyland '' because it is one of the nation 's leading dairy producers , particularly famous for its cheese . Manufacturing , especially paper products , information technology ( IT ) , and tourism are also major contributors to the state 's economy .

United States <=SEP=> The United States of America ( USA ) , commonly known as the United States ( U.S. ) or America , is a constitutional federal republic composed of 50 states , a federal district , five major self-governing territories , and various possessions .  Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico . The state of Alaska is in the northwest corner of North America , bordered by Canada to the east and across the Bering Strait from Russia to the west . The state of Hawaii is an archipelago in the mid-Pacific Ocean . The U.S. territories are scattered about the Pacific Ocean and the Caribbean Sea . Nine time zones are covered . The geography , climate and wildlife of the country are extremely diverse .   At 3.8 million square miles ( 9.8 million km2 ) and with over 324 million people , the United States is the world 's third - or fourth-largest country by total area , third-largest by land area , and the third-most populous . It is one of the world 's most ethnically diverse and multicultural nations , and is home to the world 's largest immigrant population . The capital is Washington , D.C. , and the largest city is New York City ; nine other major metropolitan areas -- each with at least 4.5 million inhabitants and the largest having more than 13 million people -- are Los Angeles , Chicago , Dallas , Houston , Philadelphia , Miami , Atlanta , Boston , and San Francisco .   Paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago . European colonization began in the 16th century . The United States emerged from 13 British colonies along the East Coast . Numerous disputes between Great Britain and the colonies following the Seven Years ' War led to the American Revolution , which began in 1775 . On July 4 , 1776 , during the course of the American Revolutionary War , the colonies unanimously adopted the Declaration of Independence . The war ended in 1783 with recognition of the independence of the United States by Great Britain , representing the first successful war of independence against a European power . The current constitution was adopted in 1788 , after the Articles of Confederation , adopted in 1781 , were felt to have provided inadequate federal powers . The first ten amendments , collectively named the Bill of Rights , were ratified in 1791 and designed to guarantee many fundamental civil liberties .   The United States embarked on a vigorous expansion across North America throughout the 19th century , displacing Native American tribes , acquiring new territories , and gradually admitting new states until it spanned the continent by 1848 . During the second half of the 19th century , the American Civil War led to the end of legal slavery in the country . By the end of that century , the United States extended into the Pacific Ocean , and its economy , driven in large part by the Industrial Revolution , began to soar . The Spanish -- American War and confirmed the country 's status as a global military power . The United States emerged from as a global superpower , the first country to develop nuclear weapons , the only country to use them in warfare , and a permanent member of the United Nations Security Council . The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the world 's sole superpower . The U.S. is a founding member of the United Nations , World Bank , International Monetary Fund , Organization of American States ( OAS ) , and other international organizations .   The United States is a highly developed country , with the world 's largest economy by nominal GDP and second-largest economy by PPP . Though its population is only 4.3 % of the world total , Americans hold nearly 40 % of the total wealth in the world . The United States ranks among the highest in several measures of socioeconomic performance , including average wage , human development , per capita GDP , and productivity per person . While the U.S. economy is considered post-industrial , characterized by the dominance of services and knowledge economy , the manufacturing sector remains the second-largest in the world . Accounting for approximately a quarter of global GDP and a third of global military spending , the United States is the world 's foremost economic and military power . The United States is a prominent political and cultural force internationally , and a leader in scientific research and technological innovations .