This paper investigates the properties of plasmons in graphene–boron nitride (h-BN) heterostructures using near-field microscopy. The authors encapsulate graphene between two layers of h-BN to achieve high-quality plasmon confinement and low damping. They find that the plasmon damping is primarily due to intrinsic thermal phonons in graphene and dielectric losses in h-BN, with impurity scattering playing a minor role. The study demonstrates that the h-BN encapsulation significantly reduces plasmon damping, enabling strong field confinement and low propagation damping. This combination of high confinement and low damping makes the graphene–h-BN heterostructure an excellent platform for developing graphene-based nano-photonic and nano-optoelectronic devices, such as single-photon nonlinearities and plasmon lenses. The results highlight the potential of these materials for advanced metamaterials and plasmonics applications.This paper investigates the properties of plasmons in graphene–boron nitride (h-BN) heterostructures using near-field microscopy. The authors encapsulate graphene between two layers of h-BN to achieve high-quality plasmon confinement and low damping. They find that the plasmon damping is primarily due to intrinsic thermal phonons in graphene and dielectric losses in h-BN, with impurity scattering playing a minor role. The study demonstrates that the h-BN encapsulation significantly reduces plasmon damping, enabling strong field confinement and low propagation damping. This combination of high confinement and low damping makes the graphene–h-BN heterostructure an excellent platform for developing graphene-based nano-photonic and nano-optoelectronic devices, such as single-photon nonlinearities and plasmon lenses. The results highlight the potential of these materials for advanced metamaterials and plasmonics applications.