The health and well-being of mothers are essential for a thriving and prosperous society, yet maternal mortality remains a pressing public health problem in the USA. We aimed to examine the US trends in maternal mortality from 1999 to 2020 based on age, race/ethnicity, and census region. Data from the Centers for Disease Control and Prevention's Wide-ranging Online Data for Epidemiologic Research were used to identify maternal mortality cases. Temporal trends were analyzed using Joinpoint regression. Annual percentage changes, average annual percentage changes, and 95% confidence intervals were calculated. The maternal mortality rate in the USA increased from 1999 to 2013, but has stabilized since then until 2020 (APC = - 0.1; 95% CI: - 7.4, 2.9). However, there have been recent increases among Hispanics at a rate of 2.8% per year (95% CI: 1.6, 4.0) from 1999 to 2020. The rates stabilized among non-Hispanic Whites (APC = - 0.7; 95% CI: - 8.1, 3.2) and non-Hispanic Blacks (APC = - 0.7; 95% CI: - 14.7, 3.0). Maternal mortality rates increased among women aged 15-24years at a rate of 3.3% per year (95% CI: 2.4, 4.2) since 1999, among women aged 25-44years at a rate of 22.5% per year (95% CI: 5.4, 34.7), and among women aged 35-44years at a rate of 4% per year (95% CI: 2.7, 5.3). Regional disparities existed, with rising rates in the West at a rate of 13.0% per year (95% CI: 4.3, 38.4), and stable rates in the Northeast (APC = 0.7; 95% CI: - 3.4, 2.8), Midwest (APC = - 1.8; 95% CI: - 23.4, 4.2), and South (APC = - 1.7; 95% CI: - 7.5, 1.7). While maternal mortality rates in the USA have stabilized since 2013, our analysis reveals significant disparities by race, age, and region. Therefore, it is essential to prioritize efforts to improve maternal health outcomes across all population subgroups to achieve equitable maternal health outcomes for all women.