diff --git a/Docs/sphinx_documentation/source/Basics.rst b/Docs/sphinx_documentation/source/Basics.rst
index dd4e53d455e..dc3022f7e12 100644
--- a/Docs/sphinx_documentation/source/Basics.rst
+++ b/Docs/sphinx_documentation/source/Basics.rst
@@ -2549,7 +2549,11 @@ The basic idea behind physical boundary conditions is as follows:
            Reflection from interior cells with sign
            changed, :math:`q(-i) = -q(i)`.
 
--  For external Dirichlet boundaries, the user needs to provide a
+       user_1, user_2 and user_3
+           "User".  It is the user's responsibility to write a routine
+           to fill ghost cells (more details below).
+
+-  For external Dirichlet and user boundaries, the user needs to provide a
    callable object like below.
 
    .. highlight:: c++
@@ -2564,7 +2568,7 @@ The basic idea behind physical boundary conditions is as follows:
                             const BCRec* bcr, const int bcomp,
                             const int orig_comp) const
            {
-               // external Dirichlet for cell iv
+               // external Dirichlet or user BC for cell iv
            }
        };
 
diff --git a/Docs/sphinx_documentation/source/LinearSolvers.rst b/Docs/sphinx_documentation/source/LinearSolvers.rst
index a1df8760f3a..d893859e7c2 100644
--- a/Docs/sphinx_documentation/source/LinearSolvers.rst
+++ b/Docs/sphinx_documentation/source/LinearSolvers.rst
@@ -209,8 +209,8 @@ function
 
 ::
 
-    void setDomainBC (const Array<BCType,AMREX_SPACEDIM>& lobc,  // for lower ends
-                      const Array<BCType,AMREX_SPACEDIM>& hibc); // for higher ends
+    void setDomainBC (const Array<LinOpBCType,AMREX_SPACEDIM>& lobc,  // for lower ends
+                      const Array<LinOpBCType,AMREX_SPACEDIM>& hibc); // for higher ends
 
 The supported BC types at the physical domain boundaries are
 
@@ -761,4 +761,3 @@ An example (implemented in the ``MultiComponent`` tutorial) might be:
 See ``amrex-tutorials/ExampleCodes/LinearSolvers/MultiComponent`` for a complete working example.
 
 .. solver reuse
-
diff --git a/Src/Base/AMReX_BC_TYPES.H b/Src/Base/AMReX_BC_TYPES.H
index ea24a64addf..b735da6fddb 100644
--- a/Src/Base/AMReX_BC_TYPES.H
+++ b/Src/Base/AMReX_BC_TYPES.H
@@ -73,7 +73,10 @@ enum mathematicalBndryTypes : int {
     foextrap     =  2,
     ext_dir      =  3,
     hoextrap     =  4,
-    hoextrapcc   =  5
+    hoextrapcc   =  5,
+    user_1       = 1001,
+    user_2       = 1002,
+    user_3       = 1003
 };
 }
 
@@ -102,4 +105,3 @@ enum mathematicalBndryTypes : int {
 #endif
 
 #endif
-
diff --git a/Src/Base/AMReX_bc_types_mod.F90 b/Src/Base/AMReX_bc_types_mod.F90
index c326d49e419..c1c6f237ba8 100644
--- a/Src/Base/AMReX_bc_types_mod.F90
+++ b/Src/Base/AMReX_bc_types_mod.F90
@@ -15,6 +15,9 @@ module amrex_bc_types_module
   integer, parameter, public :: amrex_bc_ext_dir      =  3
   integer, parameter, public :: amrex_bc_hoextrap     =  4
   integer, parameter, public :: amrex_bc_hoextrapcc   =  5
+  integer, parameter, public :: amrex_bc_user_1       =  1001
+  integer, parameter, public :: amrex_bc_user_2       =  1002
+  integer, parameter, public :: amrex_bc_user_3       =  1003
 
   integer, parameter, public :: amrex_pbc_interior    = 0
   integer, parameter, public :: amrex_pbc_inflow      = 1