Quantitative data on muscle volume (MV) are important for estimating maximal muscle power. The objective of this study was to determine the correlation between anatomical cross-sectional areas (ACSAs) and the MV in thigh muscles (extensors, flexors, adductors, and sartorius) in perimenopausal women, and to identify at which proximal-to-distal level a single-slice ACSA measurement with magnetic resonance imaging (MRI) displays the highest correlation in each of these. Axial MRIs of the thigh were acquired in 41 perimenopausal women aged 50.8 ± 3.2 years. Segmentation of the extensors, flexors, adductors, and the sartorius was performed between the femoral neck (0%) and the distal end of the intermediate vastus (100%). MVs were determined by numerical integration, and the ACSA was calculated from three-dimensional reconstructions at 10% intervals from proximal to distal. The extensors contributed 50%, the flexors 19%, the adductors 28%, and the sartorius 3% of the total thigh MV. Maximal correlations between ACSA and MV were observed at the 20–40% proximal-to-distal level in the extensors (R2 = 0.73), at 30% in the adductors (R2 = 0.82), and at 70% in the flexors (R2 = 0.72) and sartorius (R2 = 0.85), respectively. ACSA at 50% displayed the highest overall correlations (R2 ≥ 0.69) with MV for all muscle groups. Single-slice ACSAs from MRI displayed high correlations with MVs. Although the (proximal to distal) measurement locations with the highest correlation varied between the muscle groups, a single slice at the 50% location achieved the best compromise in terms of correlation between ACSA and MV across extensors, flexors, adductors and the sartorius.