Which preposition to use with lhassa

across Occurrences 1%

While England was suffering the worst of the disasters of the recent war in South Africa the Russian government sent a secret embassy to Lhassa, carrying rich presents and large sums of money to the Grand Lamal for the ostensible purpose of securing permission to construct a branch from its Siberian Railway to Lhassa across Chinese Turkestan.

by Occurrences 1%

That means the permanent occupation of Lhassa by a British army and the opening of an unknown and mysterious region to trade.

Which preposition to use with  lhassa