Quantitative measurements of lung microvessels would benefit characterization of vascular function and remodeling in pulmonary vascular diseases. Previous studies have evaluated the utility of micro-CT in conjunction with exogenous radiopaque silicone polymer injection (Microfil) to visualize vascular networks in whole organs. However, micro-CT resolutions are limited and Microfil perfusion may lead to incomplete vessel filling and vessel rupture. Optical coherence microscopy (OCM) enables depth-resolved volumetric imaging of tissue scattering with micron isotropic resolution and may be an alternative to micro-CT. Here, we present a novel method for quantitative measurements of lung vasculature using multi-volumetric OCM. Murine lungs were perfused with scattering contrast, fixed, and optically cleared. The lungs were then imaged using a custom-built OCM system with overlapping volumetric datasets and mosaicked in post-processing. OCM data was collected on a custom-built SD-OCT system and integrated with a control system to synchronize OCM data acquisition/archiving with three-axis motorized stages for multi-volumetric mosaicking. A Bessel illumination scheme was used to extend the Rayleigh range and depth-of-field by ~40% while maintaining high lateral resolution. A cleared lung lobe was imaged with 840 OCM volumes (7x12x10) that were acquired over an 8x13x1.43 mm slab with ~2 μm isotropic resolution. The resulting data was segmented in post-processing to quantify vessel diameters. We believe this proof-of-concept demonstrates the utility of our OCM and tissue preparation approach, which can be extended to compare microvasculature changes in entire lung lobes in animal models of pulmonary disease.