Placement of Monolithic Inter-tier Vias (MIVs) within monolithic three dimensional (3D) integrated circuits (ICs) (3DICs) using clustering to increase usable whitespace is disclosed. In one embodiment, a method of placing MIVs in a monolithic 3DIC using clustering is provided. The method comprises determining if any MIV placement clusters are included within a plurality of initial MIV placements of a plurality of MIVs within an initial 3DIC layout plan. The method further comprises aligning each MIV of the plurality of MIVs within each MIV placement cluster in the initial 3DIC layout plan at a final MIV placement for each MIV placement cluster to provide a clustered 3DIC layout plan.