A high-speed $(\mathrm{47,000}\mathrm{A}\text{- scans}∕\mathrm{s})$ , ultrahigh axial resolution Fourier domain optical coherence tomography (OCT) system for retinal imaging at $\sim 1060\mathrm{nm}$ , based on a $1024\text{\hspace{0.17em} pixel}$ linear array, $47\mathrm{kHz}$ readout rate InGaAs camera is presented. When interfaced with a custom superluminescent diode ( ${\lambda }_c=1020\mathrm{nm}$ , $\Delta \lambda =108\mathrm{nm}$ , $P_{\mathrm{out}}=9\mathrm{mW}$ ), the system provides $3.3\mu \mathrm{m}$ axial OCT resolution at the surface of biological tissue, $\sim 4.5\mu \mathrm{m}$ in vivo in rat retina, $\sim 5.7\mu \mathrm{m}$ in vivo in human retina, and $110\mathrm{dB}$ sensitivity for $870\mu \mathrm{W}$ incident power and $21\mu \mathrm{s}$ integration time. Retinal tomograms acquired in vivo from a human volunteer and a rat animal model show clear visualization of all intraretinal layer and increased penetration into the choroid.