diff --git a/src/input_xml.F90 b/src/input_xml.F90
index 078b00bc76..e05edd524a 100644
--- a/src/input_xml.F90
+++ b/src/input_xml.F90
@@ -142,6 +142,30 @@ contains
        trace_particle = trace_(2)
     end if
 
+    ! Entropy box
+    if (associated(entropy_box_)) then
+       ! Check to make sure enough values were supplied
+       if (size(entropy_box_) /= 6) then
+          message = "Need to supply lower-left and upper-right coordinates " &
+               // "for Shannon entropy box."
+          call fatal_error()
+       end if
+
+       ! Copy values
+       entropy_lower_left = entropy_box_(1:3)
+       entropy_upper_right = entropy_box_(4:6)
+
+       ! Check on values provided
+       if (.not. all(entropy_upper_right > entropy_lower_left)) then
+          message = "Upper-right coordinate must be greater than lower-left " &
+               // "coordinate for Shannon entropy box."
+          call fatal_error()
+       end if
+
+       ! Turn on Shannon entropy calculation
+       entropy_on = .true.
+    end if
+
   end subroutine read_settings_xml
 
 !===============================================================================
diff --git a/src/intercycle.F90 b/src/intercycle.F90
index 9b8cf25a66..74b728768e 100644
--- a/src/intercycle.F90
+++ b/src/intercycle.F90
@@ -16,13 +16,14 @@ contains
 
   subroutine shannon_entropy()
 
-    integer :: i_bank         ! index for bank sites
+    integer :: m              ! index for bank sites
     integer :: i              ! x-index for entropy mesh
     integer :: j              ! y-index for entropy mesh
     integer :: k              ! z-index for entropy mesh
     integer, save :: n_box    ! total # of boxes on mesh
     integer, save :: n        ! # of boxes in each dimension
     real(8), save :: width(3) ! width of box in each dimension
+    logical :: outside_box    ! were there sites outside entropy box?
 
     ! On the first pass through this subroutine, we need to determine how big
     ! the entropy mesh should be in each direction and then allocate a
@@ -43,19 +44,19 @@ contains
 
     ! initialize p
     entropy_p = ZERO
+    outside_box = .false.
 
     ! loop over fission sites and count how many are in each mesh box
-    FISSION_SITES: do i_bank = 1, n_bank
+    FISSION_SITES: do m = 1, n_bank
        ! determine indices for entropy mesh box
-       i = (fission_bank(i_bank) % xyz(1) - entropy_lower_left(1))/n
-       j = (fission_bank(i_bank) % xyz(2) - entropy_lower_left(2))/n
-       k = (fission_bank(i_bank) % xyz(3) - entropy_lower_left(3))/n
+       i = (fission_bank(m) % xyz(1) - entropy_lower_left(1))/width(1) + 1
+       j = (fission_bank(m) % xyz(2) - entropy_lower_left(2))/width(2) + 1 
+       k = (fission_bank(m) % xyz(3) - entropy_lower_left(3))/width(3) + 1
 
        ! if outside mesh, skip particle
        if (i < 1 .or. i > n .or. j < 1 .or. &
             j > n .or. k < 1 .or. k > n) then
-          message = "Fission source site outside of entropy box."
-          call warning()
+          outside_box = .true.
           cycle
        end if
 
@@ -63,6 +64,12 @@ contains
        entropy_p(i,j,k) = entropy_p(i,j,k) + 1
     end do FISSION_SITES
 
+    ! display warning message if there were sites outside entropy box
+    if (outside_box) then
+       message = "Fission source site(s) outside of entropy box."
+       call warning()
+    end if
+
     ! normalize to number of fission sites
     entropy_p = entropy_p/n
 
diff --git a/src/xml-fortran/templates/settings_t.xml b/src/xml-fortran/templates/settings_t.xml
index 71ae91bd27..c69439612e 100644
--- a/src/xml-fortran/templates/settings_t.xml
+++ b/src/xml-fortran/templates/settings_t.xml
@@ -26,5 +26,6 @@
   <variable name="cutoff_" tag="cutoff" type="cutoff_xml" dimension="1" />
   <variable name="cross_sections_" tag="cross_sections" type="word" length="255" />
   <variable name="trace_" tag="trace" type="integer-array" />
+  <variable name="entropy_box_" tag="entropy_box" type="double-array" />
 
 </template>