Background: Stomach cancer is the fifth most common cancer worldwide and has one of the lowest survival rates across all malignancies. There is a constant need to define current stomach cancer incidence and incidence-based mortality (IBM) rates among different population groups for improved clinical practice. We aimed to investigate the trends of stomach cancer incidence and IBM by population characteristics of age groups, gender and ethnic groups. Methods: Data obtained from the National Cancer Institute’s Surveillance, Epidemiology, and End results (SEER) Registry 12 were obtained to determine the incidence and IBM rate of stomach incidence from 1992 to 2020. Joinpoint Regression Analysis program was used to calculate the annual percent change (APC) for trend analysis. Results: A total of 82,810 stomach cancer patients were identified from the dataset. Most of the patients were males; N = 49,909(60.27%) and Non-Hispanic Whites, N = 40,894 (49.38%). The overall incidence rate was 8.00 (95% Confidence Interval [CI]: 7.95 to 8.06) and the overall IBM rate was 6.44 (95%CI: 6.39 to 6.49). The incidence rate of stomach cancer decreased significantly by 1.28 % per year from 1992 to 2020; however the degree of decline from 1992 to 2017, APC (-1.18, 95% CI: -1.27 to -1.04, p < .001) was lower compared to between 2017 and 2020, APC (-3.42, 95% CI: -6.08 to -1.69, p = 0.01). Conversely, IBM rate increased significantly from 1992 to 1994, APC (36.59, 95% CI: 22.51 to 52.29, p < .001) followed by a significant decrease from 1994 to 2020, APC (-1.29, 95%CI: -1.43 to -1.15, p < .001).Incidence rates reduced significantly from 1992 to 2020 for all gender, ethnic and age groups except among the Non-Hispanic Asian Indian or Alaska Native (NHAIAN) population with APC (-0.67, 95 CI% -1.93 to 0.61, p = 0.29) and < 60 years age group with APC (0.03, 95 CI % : 0.18 to 0.25, p = 0.76). Significant decline in IBM rate was observed from 2000 to 2020 across all gender, ethnicities and age groups except among the NHAIAN, APC (-0.21, 95 CI%: -1.26 to 0.84, p = 0.68) and the < 60 years age group, APC (0.16, 95 CI%: -0.33 to -0.65, p = 0.52). Conclusions: Stomach cancer incidence and IBM rates have decreased significantly over the last 20 years except in NHAIAN and < 60 years age populations. These findings suggest the need for further research focused efforts in these potentially high-risk groups.