The optical properties of gold nanorings, prepared by colloidal lithography, are investigated. Compared to solid gold particles of similar size, nanorings exhibit a redshifted localized surface plasmon (LSP) that can be tuned over an extended wavelength range by varying the ratio of the ring thickness to its radius. The measured wavelength variation is well reproduced by numerical calculations and interpreted as originating from the coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field associated with these plasmons shows uniform enhancement and polarization in the ring cavity, suggesting potential applications in near-infrared surface-enhanced spectroscopy and sensing. The experimental extinction spectra of disordered layers of identical nanoparticles deposited on glass substrates are compared with numerical calculations, which reproduce the measured spectra. The calculations also show a significant and uniform field enhancement in the ring interior, indicating the potential for enhanced nonlinear optical phenomena and improved near-infrared SERS sensitivity.The optical properties of gold nanorings, prepared by colloidal lithography, are investigated. Compared to solid gold particles of similar size, nanorings exhibit a redshifted localized surface plasmon (LSP) that can be tuned over an extended wavelength range by varying the ratio of the ring thickness to its radius. The measured wavelength variation is well reproduced by numerical calculations and interpreted as originating from the coupling of dipolar modes at the inner and outer surfaces of the nanorings. The electric field associated with these plasmons shows uniform enhancement and polarization in the ring cavity, suggesting potential applications in near-infrared surface-enhanced spectroscopy and sensing. The experimental extinction spectra of disordered layers of identical nanoparticles deposited on glass substrates are compared with numerical calculations, which reproduce the measured spectra. The calculations also show a significant and uniform field enhancement in the ring interior, indicating the potential for enhanced nonlinear optical phenomena and improved near-infrared SERS sensitivity.