Fibrous networks are an abundant group of materials present in nature or created through engineering. They are porous materials with randomly distributed fibres as the main constituent. Due to the distinctive filtration feature, they are attractive candidates for filtering and separation applications. However, stochastic nature of the fibrous networks’ microstructure makes their geometric modelling and characterisation difficult. Earlier, the effect of such descriptors as basis weight, fibre diameter and orientation distribution function on geometry of a fibrous network was investigated. However, the effect of spatial distribution of fibres in a fibrous network, i.e., of its uniformity, remains unclear. This research investigates the effect of spatial distribution of fibres (uniformity) on pore-size distribution and porosity of fibrous networks. For this purpose, several fibrous networks with different values of basis weight, fibre diameter, orientation distribution function and uniformity were generated using the developed fibre-placement method algorithm. Pore-size distribution was computed for the fibrous networks of such uniformity classes as clustered, random and uniform ones. In addition, a new porosity parameter, called quadrant-based porosity, was introduced and used to calculated porosity in a specified number of quadrants of the generated fibrous networks. The results of quadrant-based porosity analysis were compared to and demonstrated its advantage over the commonly utilised bulk porosity analysis.