The mechanical interaction between integrins and the ECM regulates processes such as adhesion and motility, as well as the remodeling of the ECM. Despite a large body of literature describing mechanoregulatory processes of integrins, the precise relationship between integrin-mediated forces and receptor lateral clustering are still poorly understood. Moreover, the fundamental structure responsible for force transduction remains unknown, and may occur at the scale of individual integrin receptors or within micron-scale focal adhesions.To address these questions, we generated hexagonal arrays of force-sensing nanoparticles and used these to visualize the mechanical forces exerted by integrins in living cells. Recently developed gold nanoparticle molecular tension fluorescence microscopy (MTFM) probes were combined with block copolymer micellar nanolithography to generate tension sensing particle arrays with precisely defined inter-particle spacings at the nanometer scale. Fluorescently labeled cyclicRGD probes were functionalized and efficiently quenched on the surface-anchored 9 nm gold nanoparticles. This probe features an entropic spring, polyethylene glycol (PEG) polymer, enabling pN tension measurements. Under cellular tension, the RGD-termini of the sensors extend away from the nanoparticle surface and fluorescence increases 10-15 fold. By using the worm-like chain model, the tension magnitude across the entire cell membrane can be calculated and mapped. In nanopatterned experiments, we fabricated gold nanoparticle arrays with 50 nm and 100 nm interparticle distance. Our results suggest that the average tension per integrin was highly dependent on RGD spacing, and therefore on integrin lateral clustering. When cultured on substrates with 50 nm spacing, fibroblast cells generated a tension of approximately 4 pN per integrin, whereas the 100 nm spacing leads to forces of 1-2 pN. This indicates that when integrin clustering is hindered, high tension forces can not be generated in part due to the instability of focal complexes.