The authors investigate the high-field electrical transport properties of metallic single-wall carbon nanotubes using low-resistance electrical contacts. They find that individual nanotubes can sustain a current density exceeding \(10^9\) A/cm\(^2\). As the bias voltage increases, the conductance drops significantly due to electron scattering. The current-voltage characteristics are explained by considering optical or zone-boundary phonon emission as the dominant scattering mechanism at high fields. An analytic theory based on the Boltzmann equation, which includes both elastic scattering and phonon emission, is developed and numerically solved to reproduce the experimental results. The study highlights the importance of understanding the scattering mechanisms in high-field transport of carbon nanotubes for potential electronic applications.The authors investigate the high-field electrical transport properties of metallic single-wall carbon nanotubes using low-resistance electrical contacts. They find that individual nanotubes can sustain a current density exceeding \(10^9\) A/cm\(^2\). As the bias voltage increases, the conductance drops significantly due to electron scattering. The current-voltage characteristics are explained by considering optical or zone-boundary phonon emission as the dominant scattering mechanism at high fields. An analytic theory based on the Boltzmann equation, which includes both elastic scattering and phonon emission, is developed and numerically solved to reproduce the experimental results. The study highlights the importance of understanding the scattering mechanisms in high-field transport of carbon nanotubes for potential electronic applications.