diff --git a/src/web/routes.rs b/src/web/routes.rs
index 44b808471..dbe888bd1 100644
--- a/src/web/routes.rs
+++ b/src/web/routes.rs
@@ -16,7 +16,11 @@ pub(super) fn build_routes() -> Routes {
     //   https://support.google.com/webmasters/answer/183668?hl=en
     routes.static_resource("/robots.txt", PermanentRedirect("/-/static/robots.txt"));
     routes.static_resource("/favicon.ico", PermanentRedirect("/-/static/favicon.ico"));
-    routes.static_resource("/sitemap.xml", super::sitemap::sitemap_handler);
+    routes.static_resource("/sitemap.xml", super::sitemap::sitemapindex_handler);
+    routes.static_resource(
+        "/-/sitemap/:letter/sitemap.xml",
+        super::sitemap::sitemap_handler,
+    );
 
     // This should not need to be served from the root as we reference the inner path in links,
     // but clients might have cached the url and need to update it.
diff --git a/src/web/sitemap.rs b/src/web/sitemap.rs
index 8c6ffa8c9..c08b167e0 100644
--- a/src/web/sitemap.rs
+++ b/src/web/sitemap.rs
@@ -1,13 +1,31 @@
-use crate::{db::Pool, docbuilder::Limits, impl_webpage, web::page::WebPage};
+use crate::{db::Pool, docbuilder::Limits, impl_webpage, web::error::Nope, web::page::WebPage};
 use chrono::{DateTime, Utc};
 use iron::{
     headers::ContentType,
     mime::{Mime, SubLevel, TopLevel},
     IronResult, Request, Response,
 };
+use router::Router;
 use serde::Serialize;
 use serde_json::Value;
 
+/// sitemap index
+#[derive(Debug, Clone, PartialEq, Eq, Serialize)]
+struct SitemapIndexXml {
+    sitemaps: Vec<char>,
+}
+
+impl_webpage! {
+    SitemapIndexXml   = "core/sitemapindex.xml",
+    content_type = ContentType(Mime(TopLevel::Application, SubLevel::Xml, vec![])),
+}
+
+pub fn sitemapindex_handler(req: &mut Request) -> IronResult<Response> {
+    let sitemaps: Vec<char> = ('a'..='z').collect();
+
+    SitemapIndexXml { sitemaps }.into_response(req)
+}
+
 /// The sitemap
 #[derive(Debug, Clone, PartialEq, Eq, Serialize)]
 struct SitemapXml {
@@ -21,16 +39,30 @@ impl_webpage! {
 }
 
 pub fn sitemap_handler(req: &mut Request) -> IronResult<Response> {
+    let router = extension!(req, Router);
+    let letter = cexpect!(req, router.find("letter"));
+
+    if letter.len() != 1 {
+        return Err(Nope::ResourceNotFound.into());
+    } else if let Some(ch) = letter.chars().next() {
+        if !(ch.is_ascii_lowercase()) {
+            return Err(Nope::ResourceNotFound.into());
+        }
+    }
+
     let mut conn = extension!(req, Pool).get()?;
     let query = conn
         .query(
-            "SELECT DISTINCT ON (crates.name)
-                    crates.name,
-                    releases.release_time
+            "SELECT crates.name,
+                    MAX(releases.release_time) as release_time
              FROM crates
              INNER JOIN releases ON releases.crate_id = crates.id
-             WHERE rustdoc_status = true",
-            &[],
+             WHERE 
+                rustdoc_status = true AND 
+                crates.name ILIKE $1 
+             GROUP BY crates.name
+             ",
+            &[&format!("{}%", letter)],
         )
         .unwrap();
 
@@ -119,19 +151,70 @@ pub fn about_handler(req: &mut Request) -> IronResult<Response> {
 #[cfg(test)]
 mod tests {
     use crate::test::{assert_success, wrapper};
+    use reqwest::StatusCode;
 
     #[test]
-    fn sitemap() {
+    fn sitemap_index() {
         wrapper(|env| {
             let web = env.frontend();
-            assert_success("/sitemap.xml", web)?;
+            assert_success("/sitemap.xml", web)
+        })
+    }
+
+    #[test]
+    fn sitemap_invalid_letters() {
+        wrapper(|env| {
+            let web = env.frontend();
+
+            // everything not length=1 and ascii-lowercase should fail
+            for invalid_letter in &["1", "aa", "A", ""] {
+                println!("trying to fail letter {}", invalid_letter);
+                assert_eq!(
+                    web.get(&format!("/-/sitemap/{}/sitemap.xml", invalid_letter))
+                        .send()?
+                        .status(),
+                    StatusCode::NOT_FOUND
+                );
+            }
+            Ok(())
+        })
+    }
+
+    #[test]
+    fn sitemap_letter() {
+        wrapper(|env| {
+            let web = env.frontend();
+
+            // letter-sitemaps always work, even without crates & releases
+            for letter in 'a'..='z' {
+                assert_success(&format!("/-/sitemap/{}/sitemap.xml", letter), web)?;
+            }
 
             env.fake_release().name("some_random_crate").create()?;
             env.fake_release()
                 .name("some_random_crate_that_failed")
                 .build_result_successful(false)
                 .create()?;
-            assert_success("/sitemap.xml", web)
+
+            // these fake crates appear only in the `s` sitemap
+            let response = web.get("/-/sitemap/s/sitemap.xml").send()?;
+            assert!(response.status().is_success());
+
+            let content = response.text()?;
+            assert!(content.contains(&"some_random_crate"));
+            assert!(!(content.contains(&"some_random_crate_that_failed")));
+
+            // and not in the others
+            for letter in ('a'..='z').filter(|&c| c != 's') {
+                let response = web
+                    .get(&format!("/-/sitemap/{}/sitemap.xml", letter))
+                    .send()?;
+
+                assert!(response.status().is_success());
+                assert!(!(response.text()?.contains("some_random_crate")));
+            }
+
+            Ok(())
         })
     }
 
diff --git a/templates/core/sitemapindex.xml b/templates/core/sitemapindex.xml
new file mode 100644
index 000000000..6c5c88184
--- /dev/null
+++ b/templates/core/sitemapindex.xml
@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<sitemapindex xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
+    {% for which in sitemaps -%}
+        <sitemap>
+            <loc>https://docs.rs/-/sitemap/{{ which }}/sitemap.xml</loc>
+        </sitemap>
+    {%- endfor %}
+</sitemapindex>