Lying across the Bay Bridge from San Francisco, the East Bay consists primarily of Contra Costa County and Alameda County. It has a unique culture that's more laid back and uncomplicated than its western neighbors. Oakland, the area's largest city, is famous for its somewhat smaller Chinatown and its beautiful waterfront Jack London Square, as well as its large port and eucalyptus-spotted hills. Berkeley, just north of Oakland, is home to the University of California and tens of thousands of students.

Here are a few of the East Bay's main cities; for more complete lists, see Inner East Bay and Outer East Bay.

• 37.7561-122.27441 Alameda - An island community separated from Oakland by a narrow channel
• 38.005-121.80582 Antioch - Fairly large city on the shoreline of the Delta
• 37.8708-122.29283 Berkeley - Home to the world famous University of California, Berkeley
• 37.972-1224 Concord - Birthplace of jazz legend Dave Brubeck
• 37.53-122.0035 Fremont - East Bay's 2nd largest city with one of the largest Afghan communities in the U.S. and the northern edge of Silicon Valley
• 37.6689-122.08086 Hayward - California State University, East Bay
• 37.782-122.2387 Oakland - The East Bay's largest city, with enough cultural diversity to rival SF
• 37.6625-121.87478 Pleasanton - One of America's wealthiest mid-size cities, with a (somewhat) historic district and numerous upscale restaurants
• 37.893-122.049 Walnut Creek - The best shopping in the Bay Area behind San Francisco

• 37.589503-121.7125211 Del Valle Regional Park - This East Bay Regional Park District park surrounds Lake Del Valle, and includes wilderness areas with canyons, woodlands, grasslands, and some quite dramatic rock formations.
• 37.8817-121.91422 Mount Diablo State Park - This 20,000-acre (80 km²) park provides great hiking opportunities on a mountain that dominates the landscape for most of central and eastern Contra Costa County. It offers an incredible viewshed, with views on clear days stretching 181 mi (291 km) to Mount Lassen.

The East Bay Regional Park District (EBRPD) manages numerous parklands throughout the East Bay. Some of them are contiguous but, in most cases, each park is separate. They also sometimes go by names like "regional wilderness", but they are still East Bay parks. The East Bay parks include several protected shorelines in the west; Del Valle Regional Park, Sunol Regional Wilderness, and Ohlone Regional Wilderness (the Ohlone Trail) in the south; and Black Diamond Mines Regional Park, Briones Regional Park, Las Trampas Regional Park, Tilden Regional Park, and Anthony Chabot Regional Park in the north. A longer list with more details can be found at the Hiking in the East Bay article. A popular destination in the EBRPD is Ardenwood House, in the Fremont area. It is a historic house with some parkland surrounding it.

What the locals call "the East Bay" is really two fairly distinct regions separated by the East Bay hills, the crest of the Berkeley Hills continuing into the Oakland Hills and the Pleasanton Ridge. In the inner East Bay west of the hills, the cities of Berkeley, Oakland, San Leandro and Hayward rise from the edge of the San Francisco Bay up the western face of the foothills. The climate tends to be temperate, the culture diverse, the transit frequent, and the traffic horrendous.

In the outer East Bay on the eastern side of the hills, the towns of Walnut Creek, Pleasanton and Livermore lie in the area known as the Tri-Valley region (named for the Livermore, San Ramon and Amador valleys). The climate here is more like that of the San Joaquin Valley, with foggy winters and scorching summers. The population is more homogeneous, but the traffic is still pretty awful in some places and during the rush hour. Originally, when the small towns of the Tri-Valley area began to grow into suburbs in the 1970s, many people commuted over the hills to work in the South Bay, the Peninsula or the City. Today, many large corporations have offices in the Tri-Valley area, and the suburbs of Pleasanton and Walnut Creek are growing into small cities.

The historical change in the East Bay has been from Native American tribal lands to Spanish, then Mexican ranches; then to farms, ranches, and orchards; then multiple city centers and suburbs. In general, the more urban an area is, the less obvious this progression is, and the more you have to dig to find it.

Contra Costa County is divided into three parts simply referred to as: "West County" near Richmond, "Central County" for the booming area near Walnut Creek, Concord, and Mount Diablo, "East County" for the area near the Delta which includes Antioch or Brentwood.

Though pro sports have seen a dramatic exit from the area, the East Bay has two NCAA Division I sports programs:

• The California Golden Bears field teams in 30 sports. Through the 2023–24 school year, most teams play in the Pac-12 Conference, but that league was the main casualty of the early-2020s conference realignment. Despite the geographic oddity, the Bears will join the Atlantic Coast Conference for 2024–25 and beyond. Most Cal sports venues on campus, with the most notable being the ancient Memorial Stadium (football), which sits right over the Hayward Fault.
• The Saint Mary's Gaels, representing Saint Mary's College in Moraga, field teams in 19 sports, mostly in the West Coast Conference. Unlike Cal, Saint Mary's doesn't have a football team. Men's basketball is the hot-button sport here, with NCAA tournament appearances not unheard of.

See also: Bay Area public transit

The local scenery consists of some rolling peaks, higher mountains, and wooded regions in the west. Mount Diablo sticks out like a sore thumb toward the north; in the south, generally the mountains are parts of ridges, so they do not stand out so much. The picture on the right is a fairly good example of countryside on the southern side of the East Bay.

The urban areas in the west of the East Bay can be gritty, but there are some quality museums, interesting cityscapes, and vibrant arts scenes. UC Berkeley is a highlight.

The East Bay Regional Park District maintains 65 parks across the East Bay, ranging from easy access picnic areas to off-limits wildlife sanctuaries. More than a dozen campsites range from "family camping" to backpack areas.

Berkeley and Oakland have frequent events, and the outer parts of the region have some as well, like the Alameda County Fair in Pleasanton.

The University of California, Berkeley (often called "UC Berkeley" or just "Cal") is world renowned for its educational standards and its liberal viewpoint of most things. There is a Cal State school in Hayward (CSU East Bay - formerly known as "CSU Hayward"). There are many two year junior colleges here but one of the biggest is Diablo Valley College, in Pleasant Hill.

There are many malls and shopping centers in the East Bay. Sunvalley Mall (Concord), Stoneridge Mall (Pleasanton), Bay Fair Mall (San Leandro), Newpark Mall (Newark), and Southland Mall (Hayward) are some of the largest.

The two main area codes are (510) for the inner East Bay, and (925) for the outer East Bay. In 2019, (341) was introduced as an overlay for the (510) area, but "the 510" remains a symbol of local identity in the inner East Bay.

• North Bay – not as densely populated as other parts of the Bay Area, but home to wine country and natural scenery.
• South Bay – this is where San Jose and Santa Clara can be found, and is known for being a major center of technology.
• The Peninsula – a suburban region on the west side of the San Francisco Bay and is a peninsula that goes from the South Bay to the Golden Gate.