Newcastle is a city located in Washington. With a 2020 population of 13,316, it is the 74th largest city in Washington and the 2515th largest city in the United States. Newcastle is currently growing at a rate of 4.00% annually and its population has increased by 28.29% since the most recent census, which recorded a population of 10,380 in 2010. Newcastle reached it's highest population of 13,316 in 2021. Spanning over 4 miles, Newcastle has a population density of 2,993 people per square mile.
The average household income in Newcastle is $178,768 with a poverty rate of 3.63%. The median rental costs in recent years comes to $1,814 per month, and the median house value is $759,500. The median age in Newcastle is 39 years, 39.4 years for males, and 38.4 years for females. For every 100 females there are 98.0 males.