Variation in mean menarcheal age is a global phenomenon and is influenced by a number of community-specific factors. The present paper endeavours to ascertain the mean age at menarche within two endogamous communities: the Kisan tribe (including Nagesia tribe who are the same as Kisan) of Duars and the Kisan claimants of Malda district. A sample of 602 eligible girls and women participated in this comparative analysis, with 301 hailing from Kisan tribe (aged 10-66 years) and 301 from the Kisan claimants (aged 9-80 years); the mean menarcheal age of both groups are calculated as 12.99 ± 0.18 years and 12.46 ± 0.07 years respectively. Furthermore, the findings unveiled a discernible secular trend concerning age at menarche within these communities, results reveal a decrease of approximately 3.56 months (KT) and 4.53 months (KC) per decade in these populations. The study also reveals significant negative correlation estimates between the mean age at menarche and the birth year of Kisan and Kisan claimants (-0.415 and -0.614, respectively), indicating that with the decrease in age of the respondents, the mean age at menarche also tends to decrease. The linear regression analysis (F = 62.279 and 180.826) supports this finding, showing a statistically significant negative association. This means that over time, there is a trend towards earlier menarche in these populations. These results highlight the reproductive patterns and trends within the studied communities, suggesting a potential shift towards earlier menarche over time.