Background: Understanding the structural dynamics of the heart across diverse demographics sheds light on cardiac function, pathology, and therapeutic interventions. This study aimed to determine the histological and morphometric features of the heart's layers, particularly the left atrium (LA) and left ventricle. Methods: Heart samples were obtained from 32 cadavers, comprising both male and female individuals, across four age groups (≤ 29, 30-39, 40-49, and ≥50). These samples were sourced from the forensic center of Azadi Teaching Hospital in Kirkuk city between March 2023 and August 2023. Results: Morphometric analysis revealed that the mean thickness of the epicardium layer varied among the four age groups of the left atrium (LA), ranging from a minimum mean of 103.5 μm in females to a maximum mean of 928.5 μm in males. Similarly, the mean thickness of the myocardium layer of the LA ranged from a minimum mean of 1649 μm in females to a maximum mean of 3176 μm in males. In the left ventricle (LV), the minimum mean thickness of the epicardium layer across the age groups was 217.5 μm in females, while the maximum mean thickness was 1377 μm in males. The minimum mean thickness of the myocardium layer of the LV was 1666 μm in females, and the maximum mean was 4132 μm in males. Conclusion: The study findings indicate that the myocardium layer of both the left atrium and left ventricle is thicker than the epicardium layer in individuals aged between 25 and 57 years. Furthermore, the thickness of both layers was observed to be thinner in females compared to males.