State-of-the-art first-principles calculations based on density-functional theory were performed on CH3(CH2)(n-1)S-Au(1 1 1) systems. We show that the adsorption site of methylthiolate at a range of coverages on the Au(1 1 1) surface is the fee site, not the hcp site as has been recently reported. Further, we report that increasing alkane chain length enhances the fee site preference. Study of the electronic structure of the system underscores the importance of sulfur 3d orbitals to thiol chemisorption.