6. For a positive integer, if it reads the same forward and backward, it is called a "palindrome" (such as $1, 11, 121$ are palindromes, while 110 is not a palindrome). If all palindromes are arranged in ascending order:
$1,2, \cdots, 9,11,22, \cdots$.
Then the 2012th palindrome is ( ).
(A) 1011101
(B) 1013101
(C) 1021201
(D) 1030301
6. B.

Since there are 9 one-digit palindromic numbers, 9 two-digit palindromic numbers, 90 three-digit palindromic numbers, 90 four-digit palindromic numbers, 900 five-digit palindromic numbers, and 900 six-digit palindromic numbers, there are a total of 1998 palindromic numbers from $1 \sim 999999$.

Thus, $1000001, 1001001, 1002001$, $\cdots, 1009001$ are the 1999th to 2008th palindromic numbers.
The next palindromic numbers are $1010101, 1011101, 1012101$, $1013101, \cdots$.
Therefore, the 2012th palindromic number is 1013101.