After the Mexican-American war in 1848, American rule was established in California in 1850, the Yorba lands were amongst the very few to be preserved.
In 1870, Captain S.S. Dunnells guided a ship called the “Vaquero” into an unnamed harbor. Captain Dunnells, feeling distinctly uncreative, decided to call the harbor "New Port."
In September 1870, Captain Samuel S. Dunnells’ steamer Vaquero ventured into the bay to offload a cargo of lumber and shingles. Captain Dunnells soon established “Newport Landing” by constructing a small wharf and warehouse near the west end of the present Coast Highway/Newport Bay Bridge. 
In 1875, James McFadden and his younger brother Robert acquired the landing and for the next nineteen years operated a thriving commercial trade and shipping business. However, the bay was not yet a true harbor and sand bars and a treacherous bay entrance caused the McFadden Brothers to move the shipping business to the oceanfront by constructing a large pier on the sand spit that would become the Balboa Peninsula. The site was ideal because a submarine canyon (Newport Submarine Canyon), carved along with Newport Bay by the ancient Santa Ana River, provided calm waters close to the shore.
In 1888, McFaddens decided their shipping business would be more successful if they moved it from the inner shores of the bay to the oceanfront were it was connected by rail to Santa Ana. So they built McFaddens’ Wharf at the location where the Newport Pier is today. “McFadden Wharf soon became the largest business in newly created Orange County”, California. It lasted for eight years, the McFadden Wharf area was a booming commercial and shipping center and a company town began to grow. However, in 1899, the Federal Government allocated funds for major improvements to a new harbor at San Pedro, which would become Southern California’s major seaport. The McFadden Wharf and railroad were sold to the Southern Pacific Railroad that same year, signaling the end of Newport Bay as a commercial shipping center.
In 1902, James McFadden sold his Newport townsite and about half of the Peninsula to William S. Collins, who saw Newport Bay’s resort and recreation potential. Collins took on Henry E. Huntington as a partner in the Newport Beach Company. Huntington had acquired the Pacific Electric railway system and used it to promote new communities outside of Los Angeles. 
In 1905, the Pacific Electric “Red Cars” were extended to Newport. Collins began dredging a channel on the north side of the bay and deposited the sand and silt on tidelands that would become Balboa Island. Formerly known as Balisle, this enchanting little island was not always easy to get to. Newport Harbor was still largely undredged, and sailboats were often the only way to get around. Robert McFadden, an early Balboa Harbor developer had established a successful fishing wharf on the Balboa Peninsula.
In 1906, the Pacific Electric line Red Cars began service to the Balboa Peninsula and Pavilion, and soon, the Red Cars would bring thousands of summertime visitors from Los Angeles.
In 1906 the Balboa Pavilion was completed along with her sister project, the Balboa Pier (for the purpose of attracting lot buyers to the Balboa Peninsula part of Newport—- History has abundantly proven that the plan worked!). Back then, bayfront houses sold for as little as $500.
Further, in 1906, Newport Beach became a tourist destination with the arrival of the Pacific Electric Railway. The railway terminated at the Balboa Pavilion.
Still further, in August 1906, Newport Beach became incorporated as a city.
In 1908, John Scarpa, an Italian gondolier, put together the first Christmas lights boat parade in Newport Harbor. This started a long, yearly tradition that has lasted to this day.
In 1908 and 1909, with permission of the Orange County Board of Supervisors, William Collins moved his small dredge to the eastern part of the Newport bay, a mud flat called "Snipe Island," and begin cutting a channel along the north side of the bay across from the Pavilion, pilling the sand and silt up on the mud flat and thus Balboa Island was born. Balboa Island was a summer vacation place. Most homes had no heaters, and were closed up in the winter. Families came down for the entire summer. Cooking was done on a gasoline stove as there was no gas or electricity. Coal oil lanterns and candles were used. 
In 1909 The first "seawall", a wooden bulkhead that protected part of the Island, was built. 
In 1910, The McFaddens sell Newport, Lido and Balboa Island for US$35,000.
Newport Beach and Balboa Island, 1921.
In 1912 The seawall was partially replaced by a cement barrier (cheap German cement). 
in 1914, Water lines to the Island were first laid. 
In 1916, Balboa Island is annexed to city of Newport Beach.
In 1919, water for the Island came from the famous "Wooden Water Tower" built on Agate St. (removed in 1929). 
In 1920, Park Ave. was the only road paved on the Island. People had outhouses behind their house as there was no sewer. They buried trash in big holes dug in vacant lots. Also in this same year, gas utility came to the Island (heating, cooking, lights). 
In 1919, Joseph Beek, while still a student at Pasadena City College, was enchanted with the area, and became one of Collins' salesmen. Joe Beek played a crucial role in the development of Balboa Island, and spent a lifetime devoted to it. Joe got the first contract for a ferry between the Island and Balboa Peninsula. 
In 1920, the first car was pushed across the bay (for 10 cents). In 1922, Joe Beek got a 15 year franchise, using the ferry boat "Joker", which could hold two cars. That franchise has continued until this day, with three 64 ft. boats that can carry three cars. He later served as Secretary of the California State Senate until his death in 1968. 
In 1922, The seawall was rebuilt. 
In 1923, the city annexed Corona del Mar.
In 1926, the Pacific Coast Highway was built through the city. Also a bridge over the Upper Bay was built.
In 1929, The Grand Canal wooden bulkhead and walk were rebuilt in concrete. 
In 1936, Newport Harbor was officially dedicated. This occurred after a $1.8 million project dredged out the sandbars and extended the jetties.
In 1938, James Cagney, a famous Hollywood actor at the time, purchased Collins Island. The US Coast Guard used this island during WWII and Cagney eventually sold the island in 1948.
Later in the 20th Century, Newport Beach became the home of a number of famous celebrities. The most popular Newport Beach celebrity was John Wayne, also known as “the Duke.” Other celebrities residing and/or keeping boats in Newport Beach included James Cagney, Humphrey Bogart, Shirley Temple, and Errol Flynn. Furthermore, "Roy Rogers and Dale Evans" as well as George Burns resided in Newport Beach. Other notables included television star, Buddy Ebsen (Beverly Hillbillies, Barnaby Jones), as well as Johnny Carson’s most frequent guest host, Joey Bishop.
In 1953, the third international jamboree of the Boy Scouts of America held its event where Newport Center and Fashion Island now sit. It was the first jamboree held west of the Mississippi River and had with 50,000 scouts from all 48 states, Alaska, Hawaii and 16 foreign countries. Thousands of tents were pitched in the area reachable only by a two-lane muddy trail called Palisades Road. The road was soon paved, and later the name was changed to Jamboree Road in honor of the Scouts.
In 1958, Hughes Aircraft Company's Solid State Products Division, and Microelectronic Circuits Division, specializing in electronic testing, and assembly of hybrid components and administrative activities, was built in Newport Beach. Throughout the years, various use permit approvals were granted for the expansion of the site. In 1997, Raytheon Company merged with Hughes, and subsequently acquired the site. Raytheon continued the established operations. Raytheon sold the site in 2000.
In 1967, Fashion Island was completed. Newport Center Drive, a circular road, embraces Fashion Island and gives it the "island" name.
In 1962, Pacific Electric trains along the Pacific Ocean are used for the last time to deliver boats to Newport Beach.
In 1990, construction began on Newport Coast. Of professional basketball fame, Kobe Bryant resides in Newport Coast today.